I play as a Avian/Warrior this age and never had a problem with lacking off during wars, go into them with a decent TPA and 25% hosps and your fine. Biggest problem i've ever had was lack of pezzies due to having to have a large EPA to compensate training during wars, but thats what the TPA is for. Knowing when to send every leet out and when not to is also important for saving leets imo, if your a designated shell tgt then keep your leets out (if your recieving heavy NS/Prop is one such example). Over time you'll be able to judge when you'll be heavily hit and if you judge those times right then you can send out all your leets and enjoy some topfeeding for a bit.

I spend nx to no GC in wars, main cost is building on acres, the credits are more than enough for def growth during a war and if you start out with decent EPA and TPA then those are the other main costs. Dropping your PR to 50% for a tick (or 2) then back up can also help in leet funding, if you do this directly after you hit then it you'll have enough time to counter the couple hours 'damage' to your ME. Also while it's all going good and your not being hit, don't spend every credit you get, I've found that you should always expect to be hit, saving roughly 10% credits each hit helps in any recovery. Credits can't be stolen so use that to your advantage as well, for example make a few TM before war and get yourself razed down so you don't need to spend the credits you've just obtained, just bear in mind that you'll most likly need dropping to roughly 85-90% of your original size due to def losses. (I know this sounds like exploiting the system a bit, i did say something prior to leaving for years and still not changed so can only assume it's ok to do)

To cut it short, to deal with military losses it is ideal to understand where you'll be losing them and planning pre-emptivly.