Question about vesc’s

Right now I am building my parts list and the part I am stuck on is the vesc. Firstly I don’t know what amp rating I need and secondly there’s so many bad reviews with flipsky even though a lot of people say they work just fine. With the amp rating, I am going to be running a single 6374 85 amp motor and I would like to try to maximize as much power as possible out of this motor, especially going up hills and such, so would I need to buy an esc that is rated over 80-85 amps or can I use a 70amp esc continuous but set it to run a max of around 80 amps (since I would be most of the time under the rated limit)?

Also with regards to flipsky, I am really just trying to save a bit of money with purchasing from them if possible, but I am also considering a SV6 from makerX, though it’s about 70 dollars more.