I experimented with recoil springs a while back. My CZ-75B was really chucking the brass out there {10-15 ft.}; so I decided to swap out the recoil spring since it always seemed a bit light. I tried both the Wolff 16# Variable & the 17# Conventional springs for the Hi-Power. Here's what I found...
16# Variable:
Was a great fit right out of the package. Was a step up from the factory. Felt a lot more solid, gave no function problems and did help tame muzzle flip.
17# Conventional:
Was too long & to heavy initially. I couldn't even get it in the pistol.
I solved this by keeping it compressed overnight. 3/16" threaded bar + 2 nuts and washers. Don't completely compress it. Just take it down to about three inches or so and let it sit a while. This caused it to take a 'set,' shrinking it about half an inch or so. However I still had to clip off about 1.5 coils. Now it would go in without causing binding/scraping when the slide was racked.
I've kept the 17# Conventional in it. It just feels right for me. The recoil impulse is improved {although that's subjective}, and the brass is deposited 4'-6' feet away.
I don't think you can go wrong either way. Neither caused reliability issues and both seemed to make overall handling better.
Best of luck.