If you get an 860 EVO it wont matter what you use it for, it will outlast whatever system you put it in. Stock over provisioning is 10% and this is the choice made by vendors after many generations of R&D. Increasing over provisioning wont break anything but it also isn't going to improve anything, at least on current generation SSD technology, it was different in the past when this technology had not yet matured. Currently the sweet spot for price to performance is a 256GB SSD and a larger HDD for stuff that does not need to be fast, get one as large as you need or reuse one you already have. The 256GB 860 EVO is under 100$ and should be absolutely bullet proof. There are other good brands but Samsung really has a made a name for themselves when it comes to great SSDs.
Just an update - received feedback from Samsung on the topic (took them a while to respond) Secure Erasing the SSD via booting in DOS does not use TRIM! The whole process took something less than 10secs, so I guess I didn't put too much strain on it (and yes, I did had to physically disconnect/connect the SSD)