Remote resevoir questions

[LowBuckX]

Im building my own remote resevoir tank and need a little info.

How much fluid should it hold? Im running a cooler if that makes a diff.

Are the after market tanks vented? If so how? A simple hole or a pop off afair like a rad cap.

What I have so far holds about 9 1/2 OZ about the same as the Zoops in dimention I can make a tandem tank to double this if nessisary. Mine Is baffled also

Thanks guys.

*****I just measured my stock p pump tank and it holds 10 OZ*********** I also just found a 32 OZ alternative that will use my baffles.