I've generally had lighter switches, and have done spring swaps to keep them light- those Gateron Clears were once Blacks, but the 70g linears were a bit much for me to type consistently. fatigue has never been much of an issue outside of cheap domes or chiclet keys.
Buckling springs aren't lighter in actuation, but there is a good amount of force springing your fingers back up after a stroke, making it pretty easy to move from key to key. In that way, they are some of the best typists switches, IMO.
It's also true that even if you decide to go 55g and dislike it, it seems like everyone likes 55g Topre, and flipping it wouldn't be too hard.