I'm trying to log the performance changes but some tweaks are hard to quantify like cpu and ram usage... i would need a permanent logging of toph, but all that i know, since my first computer in 1992, is that the less stuff you have running, the better it is.
So you wonder if those modifications are good for the Pi ? Yes lol, even not noticeable, the little bits saved is better for such a device.
As for the power efficiency, i've already posted a picture, 2 hours of playing snes, megadrive and neogeo did only draw 852mAh
That means that with my 4800mAh battery, i'll be able to play around 11 before charging

This test was done with an overclocked Pi Zero hahahaha... without overclocking should drop significantly
But this test was before some other tweaks i've made so the power efficiency should even be better !
I'm trying also to keep a track of SD I/O to see how much writes we saves with these tweaks