You won't need a 850W PSU for a single 1080 & an i7
The test you've posted was total system load from the wall at max stress. So the whole system (PSU, Mainboard, CPU, cooler, RAM) drew 200W from the grid, including efficiency losses.
Add another 300W for a highly overclocked card and rads and you're at 500W
A 650W unit can easily handle this. Heck, unless you're benchmarking all the time, a 550W quality PSU can handle those gaming loads.
The only reason to get a 850W unit is either to add a second GPU or to run it passively cooled in a silent build.
Before buying a PSU keep in mind that your case supports PSUs up to 160mm max, but shorter ones are recommended because cable management gets quite tricky.
Factoring that in several recommendations fall short.
A Corsair RMx or Seasonic Prime is way too long, as is the the EVGA P2, the XFX XTR and other quality supplies being at max size
The Strider is not a bad PSU but hardly justifies it's price. They cheap out at secondary capacitors and their soldering work is mediocre, neither is it one of the quietest units out there.
The small size is a big plus on the other hand.
Personally I'd go with an EVGA G3, Silverstone cut too many corners for my taste but if it comes at a good price, go for it