I think this is a “what works for you” thing.

With a two-hand grip on a springer, I’ve often had good results with a fairly weak strong hand hold and a firmer one from the support hand. That may sound and feel a bit weird, but it works.

The Webley springers are hard to do well with with a loose hold, but not impossible. I think I favour a medium hold. But that may be a cop-out. I’ve had some good moments with them, but will never claim to have really sussed out what works best.

I too have found (unscientifically) that Webley over levers are more accurate in .177” than .22” and wondered why. Is it barrel/ammo quality and compatibility? Barrel rigidity? Or as Modski suggests the shorter barrel time - or the different spring-surge characteristics of a pellet with a lower start pressure?

Finally, in my experience the BSA Scorpion shoots terribly if you grip it as if it was a .50” Desert Eagle, but shoots really well with a gentle two-handed hold. Ditto the HW45.