end game with tec, i usually have 3 fleets, 5 lv. 6 caps in each fleet, and 15 light frigs, 10 lrms, 5 flak, 3 of each carrier, etc. one fleet i have just a lv. 8 colony cap, which is more than enough to handle most assaults.
one fleet defends my galaxy, the other defends my allies galaxy, the thrid offensivly attacks.
with over 200,000 creds by end game, i can easly support all my fleets and upkeep.
tips:
1) 2 trade ports on every planet / asteroid
2) the asteroids/planets closest to the star, or the way for the enemy to attck you, should be defensively fortified. 2 repair bays, planetary shields, turrets, 2 hanger defense.
3) refineries on ice and desert planets
4) control the black market, you decide when it crashes or booms, always have atleast 500 metal and 200 crystal on the black market
5) pirates are your friend. using tec's credit strength, don't feel afraid to place over 60,000 in bounties. it keeps the enemy busy, and lets your fleet come in when their down.
6) dunov and akaan caps are a must. the dunov restores shields, and the akaan prevents enemy ships from escaping.
7) research. don't feel afraid to spend a lot of creds in research. in the long run, it pays off.
8) planet infastructure should be upgraded asap. the more people you have, the more tax you can get

hope those tips help.