Yes. JIS. JIS is superb. And my brand of choice is "Vessel", made in Japan. It is rare I allow an electric screwdriver within 10 feet of my airplanes.
Vessel ball grips are my favorite of their models.
The one I put in each aircraft is the 220-W JIS combination driver:
The one I really like in the shop is a 2200 series ratcheting ball grip:
Yes, I have the Snap-On sets and even the ubiquitous Snap-On ratcheting driver. But I find it hard to beat the quality of Vessel and the ball grips fit my hand perfectly. When I hand one to a friend and they start using it they really like the feel.
And as far as stainless screws on the aircraft, especially going into nutplates, I like to swipe the threads with Boelube or bees wax prior to installing. I also don't tighten them like Caterpillar Tractor screws. If they are visible I just snug them without cracking any paint. It all makes future maintenance much easier.
Jim