T5 or T12 vho Have icecap ballast.

[jasonak]

I have a ice cap ballast. 660 thats brand new I have radions gen 3 pro and want to supplement. So I can use either t12 or t5s. T5s will cost more as they dont have built in reflectors that I know of so im thinking t12s so I dont have to spend the money on reflectors but is there big gains or even 20 percent gain by using t5s ? I know everyone uses them now but t12s are still readily available from fosters.
Ive saw few post talking about them being about the same but they were all older.

I have 120 2x2x4 with 2 xr15 pros

thanks