Hard to say if the 60psi is okay or not...
Unless you baseline that particular compression tester to a known working gauge, it's hard to give you a definitive answer.
I've had compressor testers show 60psi on a newly built motor and end up breaking in okay.
Two things that most people miss:
1) Throttle needs to be propped all the way open - i.e. WOT; I think you mentioned this.
2) You need to remove BOTH the trailings at the same time; Mazda offers specs with both trailings pulled - you can pull both leadings, but the #'s will be slightly lower.
Not doing either or both will reward you with a significantly lower #'s.
The good news is that you get even pulses.
I'd take even pulses over the overall #'s anyday.
There's still a chance the #'s are not a true indication of the condition of the engine, or you can get the engine to break in properly.
If you get uneven pulses, you need a minor miracle to get that to fix itself.
-Ted