If I remove a screw or a machine screw I almost always replace it, especially on Gottlieb games - because I hate slot head screws. I also often change screws in Williams and Bally when I take them out of step units and such, if they look rusty.

Just plain zinc plated sheet metal screws and machine screws that I buy in bulk in various lengths. Never had any kind of galvanic reaction in over 30 years.

Pinball Resource sells Gottlieb hardware from the solid state era. I have gotten 8-32 slot pan head
screws for drum units and drop target banks. Gottlieb used slotted round head screws for the EM
drum units pinballs.

Gottlieb used slot head screws for pretty much everything.
Pretty sure they did it just to piss me off.

I took a new flat head screw driver and filed the head sides so as to be perpendicular
rather than wedge angled.. The screw driver now fits into the Gottlieb's sloted head
hardware.

Preacher! The Phillips screw head was invented in 1932, I believe Gottlieb just went around and picked up every standard screw that everyone else in the industry was throwing out to save money.

Gottlieb tip: Add a dab of contact cement to your flat tip screw driver.
It is a godsend for areas that are hard to have finger access too.

These work really well too. Klein slotted screw holder.

https://www.amazon.com/gp/product/B00093GCVO/ref=ppx_yo_dt_b_asin_title_o09_s00

"Not designed for torquing or tightening". Well of course, who would want to tighten a screw?

All the above mentioned things will make it somewhat easier to start or tighten slot head screws.
But you know what works best? Replace them with Phillips screws.

I've found that a decent quality flat blade, parallel face, screwdriver works just fine with the Gottlieb screws.

Such as the Gardner Bender or Klein insulated shaft screwdrivers. The right tool for the job.

But that's just me.

Trust me they tighten screws to acceptable torque in an EM. Especially nice when servicing a Gottlieb Coin unit where there isn't space to start the mounting screws or the coin entrance plate with recessed holes.

A magnetic screwdriver works well