First of all, macros are fine, mashing your buttons like a maniac is not. To minimize clipping you can actually feign activation of the macro, this takes skill and attention. For example, you use SS > BL > WB > Buff > VB > Buff > HS > OMG PROC ON RoB 1 SECOND BEFORE MY GCD IS UP WHAT SHALL I EVER DO????
pause
take a breath
just tap the next damaging GCD ability so it activates without activating the oGCD ability BL...

It takes a ton of practice and tricking your brain not to button mash, but you will become a better player and much more efficient.
I think maybe once in 100-200 GCDs I'll mess up and delay myself 1 second.