performance on pinches ... both wide and narrowDo i need to train big chunky pinches as well as pencil thin ones ?
I I'm sure if you are a wad they are no good for you,
I've got a couple of these on my desk.http://www.amazon.co.uk/gp/product/B0015ULV16/ref=oh_details_o06_s00_i00which I like playing with and are good for holding in finger pinches. I'm sure if you are a wad they are no good for you, but a lot easier for the average deskjockey than having a breezeblock next to your laptop.
A 4" concrete block only weighs 14kg and is pretty easy to pick up 1 handed if you cheat by using the crease in your thumb and torquing with your fingers. If however you use the pads of both thumb and fingers it is harder. Get a fair-faced (smooth) one since the friction is worse and it won't eat your hands as much. Bear in mind that they are ridiculously easy to pick up wearing labourer's gloves and are significantly harder without. A 6" block is impossible if you have barbie doll hands like mine.
Either you're a builder or you have an obsession You're dead right about the thumb crease/finger angle though. I've sanded my block down that's attached to the battery so there are no 90 degree angles to cheat with.