Minimum 160 in Surrey Hills 😉 😛
But nah, 140 is fine.
Climbing is a lot down to technique. If you climb balanced over the front and standing, you are bobbing like crazy and then the travel becomes an issue. That or you lock it out or have dual position forks. Steady seated climb is far more efficient and less travel dependent (except on single pivot bikes 😉 )
I climb on a 150 fork hard tail and 170 AM bouncer with 160 rear and really don’t notice anything between them in terms of travel effecting the climbs. No lock out.
Bike weight I do notice a bit, but only if I decide to sprint up something. I’m no sprinter though.
Descents, really doesn’t matter. People in SHills on DH rigs and some on rigid hard tails. Same trails. The DH rigs may be a pig to climb though, but more because they’re never geared low enough and are super heavy. A rigid hard tail is just a lot more suspension in the legs. Unless it’s a rigid fat bike, then it’s all in the tyres 😉