I earned a lot more parting out my old MacBook Airs than I would selling them as a full unit with well-worn charger and battery.
Learned a lot too about the internals.
And I sold every component. Even the screws.
Ebay is the best place to sell parts, yes. Prepare for some shrinkage as it's easy to scam new Ebay sellers.
Usually you just need a special screwdriver ($2-3 or so from eBay from Asia).
Ship everything in anti-static bags and reused Amazon packaging.
Why? Dont normal screw dont work in Apple devices? Or do people think they dont? Are their heads more beautiful?
As far as measurement being difficult : we're already talking about major disassembly of a device here. These fasteners are small, sure, but I would hope that anyone that is undertaking the task of disassembling whichever expensive product already knows how to manage a magnifying glass and a ruler or caliper.
With all that said : with an Apple/Lenovo/Dell product, screw sets can be had on amazon/ebay for extraordinarily cheap. Measurement and fastener acquisition only really happens on one-off models and flighty brands.
Not an apples-apples comparison, but for PCs you can buy cheap sets of standard screws you can use for a long time:
(not a referral link and I have no connection with the vendor - it was just top result in an amazon search)