I'm gonna answer the same way kei did just to add one more opinion, you'll then have to make up yours
1. I see no point in building axes. I have 600 villages and not one axe in them. They are lousy at farming. Whatever they can do, zerks do at least as better. They have a 45 strength per provision used. zerks have 50. And if they hit a stack they double that value. Also when you build zerks you are using another building to build troops, so if you get a mix of troops between cavalry, mounted archers and zerks, your nukes are not only stronger, they are also faster to build.
Now there is a downside for zerks, their price. They are very very expensive. So you should have as many as you can have without stopping your queue production in the barracks. For a player that doesn't farm, go with 0 and up to about 800 for a player that farms a lot. That's my advice.
2. Don't make mixed villages. A village is either offensive or defensive and reserve as much provisions as you can for troops. There is no point in going beyond level 25 for HQ, level 1 for HallOfOrders, and personally because I barely use the market, I wouldn't go beyond the level 10, I personally use 7. But this last one really depends on the way you play. Personally I think I loose less time to send the troops in a farm run to get the resources than to actually sending them through the market. For you to understand the difference between maxing those 3 buildings or leaving them at the level I use is almost 1.5k worth provisions that you are not using for troops.
3. LC/MA is a good and fast to build nuke. It's also versatile, because besides strong is also fast on the ground. But as Kei said, you should always have rams in your nukes. When you feel speed outweighs the strength in your choice to attack an enemy, just leave them home and send the cavalry alone.
4. As Kei said such a nuke is very useful to hit stacks. The main problem with a full zerk nuke is getting the resources to build them. If you take 2 months to build a full zerk nuke, you can build 5 normal nukes in that time, so you better just send 5 nukes against the stack than build a full zerk nuke. In my case it's not the cost of the zerks by itself but the fact that they are poor at farming, so you can't farm the resources to build them in a proper time. It also depends on your villages and if you have the patience to use the market to send enough iron for it. My markets are normally at level 7 so you can be sure I won't do that. What I try to do is build it in stages I build a MA/zerk nuke first, I use the MA to farm the resources and I can have it built in a short period of time, then I kill part of the MA and keep building zerks in its place until you have a full zerk nuke. But all this is a beautiful plan but I always end up using the nuke before doing the second part, lol
Although I've seen other players saying otherwise, I actually think the zerk nuke doesn't need rams. the value of the zerk nuke is to launch at stacks. And stacks always have too many trebs. I only have rams in them, because sometimes I launch them at normal targets but here you don't actually need them for their main purpose.
But keep this in mind, if you combine the bountiful harvest on this villages, you can add up 400ZERKS to those nukes, now add also the grandmaster when sending the attack to it. On my case that would mean 3200+400zerks+10% strength. Now send that as the first nuke against a stack, which means the zerks will be fighting at double strength, that is a powerful nuke. That's the same as launching a nuke of 52.8k axes. That is power and that can make some damage...
5. Axes or any o
ther unit. It's a wall-breaker for villages that have some trebs in them. I don't use them but I can see the use for them.
6. What you need to know is the strength per provision of each unit and the time it takes to build. And the time they take to build is important. If you take twice as much time to build, that means you could have sent 2 nukes to the enemy when you are just sending 1 even if more powerful.
strength per provision:
AXE - 45; LC - 32.5; MA - 30; ZERK - 50 (100 against stacks)
strength per recruit time
AXE - 18; LC - 21.7; MA - 20; ZERK - 15 (30 against stacks) but take into consideration that the zerks are built on a different building.
resource per strengh
AXE - 1.300w+0.667c+0.889i; LC - 0.962w+0.769c+1.923i; MA - 1.667w+1.333c+0.667i; ZERK - 4.000w+4.000c+8.000i
By the numbers you see up here you can infer that LC is probably the best unit overall. It also farms pretty well. But if you hit a spear stack you are doomed, so take this numbers and try to build a balanced nuke with them. MA are great against spears. ZERKS are powerful but they take a lot of resources. I can tell you the numbers I personally use, 2000LC+1400MA+700ZERKS+354RAMS (takes 11 days and a half to build with the 20% tribe skill or 14 and a half without it), but keep in mind that I have a very high demand on iron with that nuke not just because of the zerks but also the LC, I'm ok with that just because I'm very active and I farm a lot. On coop accounts that are dumped on me and where I don't farm I go with 2800LC+1600MA+354RAMS and no zerks. I know many players make MA/ZERK nukes because MA is high on wood while ZERKS are high on iron and they balance each other out... You have now to take all this info and adapt to your own play style now.
You can use the following spreadsheet to help you with your decisions. It's a spreadsheet I made in LibreOffice (I'm not sure how it works in excel or others) and you can test your village build with your troop build. It should also give you the provisions you are wasting everywhere and how much time it takes to build each troop build. If you put the farm level at 31, it will function as the bountiful harvest on a village with a level 30 farm.
http://sabercathost.com/Uad/TW2-VILSETUP_V0.04.ods
Feel free to use it edit, copy or whatever, I really don't care what you do with it. If you have any problem using it, let me know, I will try to help...