They look suspiciously like V brake levers to me - unless they are the type you can switch the travel setting on then I'd try some levers designed for cantis and see if that works better.
Well, I've gone and bought bargainous Shimano Deore V brakes so will be going that way. I think getting the pads to hit the rims properly might also help a lot. These frogleg brakes have no adjustment in that regard.
They look suspiciously like V brake levers to me - unless they are the type you can switch the travel setting on then I'd try some levers designed for cantis and see if that works better.