I've only shot 6 deer with mechs, and recovered all 6 with ease.
I ran 73-82# and shot heavy aluminums with NAP Spitfires to hedge my bet since a lot of junk science was in the bow mags and shops.
Pinpoint placement, blew through and stuck in the ground every time.
If your bow can't punch a mech through it might not be doing as well as it should with a fixed blade. Paper tune it.
Bump up your FOC and paper tune.
IMHO too many people have form or tune issues and slap on a mech and suddenly get decent grouping. They then think the problem has been solved.
Many times it's merely been masked.........sloppy flight can still be repeatable enough for OK grouping.
Along comes some meat and the arrow doesn't blow through and people go WTH?????
Work your arse off and achieve the best flight you can. Don't get hung up in the speed game, lose a little and get that rig shooting so you can't put more than one fixed blade head in your block at 50 yards, without major risk of nuking it on the next.
My fixed blade heads shoot that good.
But I run a little heavier arrow than some folks, higher FOC and helical feather fletch.
Boring as heck..........the lack of problems