How many support ships is the right amount

for the robotic cruisers usually 1/4 of my fleet is made up of them because if you have alot they can repair the ships in your fleet almost as fast as they get damaged. for cielo i usually have 10 or so in a huge fleet i know thats not very many other people would probably make more but i just prefer hoshinkos.

for the Vasari you want to make as many subvertors as possible. if you have enough of them you can disable most of the enemy fleet pretty quickly with its second ability i forget what its calle. and you can weaken the enemy ship's sheilds with the other ability witch then gives the rest of your fleet a better chance at destroying their fleet before yours. and the sevron Overseeers are helpful because of their reactive nanite ability they can add hull points to ships which can keep them alive longer. for the vassari you want to focus on building support ships because that is the strength in the vasari fleet.

unfortuanatly i cant help with the Advent to much because i usually don't play as them.
i hope this helps

Note these are the amount of ships that i use and Other people may suggest different amounts.

For Hoshikas, I usually have 8-14 of them. I have them in the back protecting my Caps, but if need be, they go up front. If they're under fire I use some cruisers as meat shields, AKA Kodiaks.

Cielos, I usualy have 2-4. Not a lot, if one goes down, you still have more.

as many as you need.