Roller Rockers 1.5 vs 1.6

I'd call b3 and get some input and suggestions.
A 1.6 will increase lift, which is good, but it can also amplify any potential issues you have with the valve train, and so proper spring choice and geometry is important.
Plus, B3 has extensive experience with lots of different combos and can probably help point you in the right direction.
His geometry correction kits would be worth it IMO.

Fwiw, I run stainless 1.6 rockers in my tfs heads and so far so good.