Questions about war victory

I'd like to try seriously war victory in a few months and do it with zero arranged battles or anything even if it means failing it, because at least it would be way more fun. So:

- If I remember correctly, once the trophy hall is level 5 and has all trophies, you still need to get a lot of stripes and the game doesn't even tell you how many you need, is that right ?

- I don't remember about the trophy that require to destroy all towns from a player, I think he must have at least 4 towns, but is it working even on a collectivism player once his dwelling, which cannot be completely destroyed, has all its buildings destroyed (or even despotism since they can rebuild during 24 hours) ?

From old update log:
- "Attacking Collectivism players will bring 3x more stripes for killed units and destroyed buildings that attacking Leaderism", is it the same for republic (or even 4x more since defense is 400%) ?

- "The difference in ages no longer matters as long as you are at least one age below target which is needed to qualify for stripes, however the age of the attacker is critically important from now on. If attacker is in Stone Age he will get x4.8 multiplier, for Classical Age it is around x2.5, for Medieval it is x1.3 (these numbers are subject to change throughout the development as we will be tweaking things)", back in the days renaissance was the last age, what are the multipliers now ?

Ok. All trophies looks possible by playing normally against decent players except killing settlers and destroyer/siege like said already, and the one about spying has a problem: it sure sounds interesting to use spies too for trophies, but the requirement here first require to find someone that not only made spies but made a lot, which is very rare to find since most people don't spy because they fear to be detected and thus make at most 1 per town just to detect, but even if, by spying a lot of players, you finally find one that has a lot of spies, it's very random, here is what can happen: you send 50 spies, he only had 10, you overkill them: no trophy. You come back later then, quite stupidly purposely nerfing yourself by sending less spies: this time he moved all his spies in this town and they all get killed: still no trophy. So then you send back all your spies: he expected such behavior and moved all his spies to another town, this looks funny but can make you mad. So, I think it should be replaced with something that simply require you to send a lot of spies to a lot of different towns like to discover every buildings the town has in a single spying attack (with obviously a minimum, otherwise 5 artistes sent to a 0pop 10 culture town would be enough).
I though about other types of spies too: chaika and helicopters are made more to explore than spying so you would have to be lucky to spy when they are not gone, special agents are clearly less good than the riflemen they obsolete so until space age is released I guess people don't even research them, even so their electricity cost is quite a detterent to make a lot. Last one is submarines: industrial one require sulphur and loosing the doctors for this unit that can only attack boats, and info one require uranium too, and most important: industrial submarines steal hovercrafts/ironclad slots, nuclear submarines steal global combat ships (and maybe one day carriers), so I don't expect to see a lot especially since boats are very expensive compared to land units for the same damage.