Question.
How i can put 2 pieces of equipement to compare on the research screen? I already saw someone do it on youtube but can´t repeat the process.
1-> Really depends on your necessity. Just remember to stay under the number limit (24 generals/ infinity field marshals) . Generals upgrade faster.
2-> If you can afford a general/Field M. Just for them sure. This way you will not confuse yourself sending paratroopers somewhere and find out half your army can´t do that order.
3-> Atrittion works even on peacetime. Got the same problem with Brazil. Just send the unit to someplace with high infrastructure.
4-> Nop. Make them work 100% of the time, no benefit staying idle.
5-> Yes. If you can afford go for the limit. Just remember the limit works for almost everything. (Industry both civilian and military, Dockyards, radars, refinerys, nuclear plants).
So you need to becareful to not use max slots on a province you wish to build some radars for example. Some tech increase the maximum amount (20% each until 100%).