thanks for adding to the ideas! indeed, this was one of the simplest means to limiting the speed done way back in the early days of the mini-z
i had never thought to try a tire inner tube... how do you secure it to the handle?
what i had always wanted to try but never did was tennis racket handle tape. it's offers very good grip, nicely padded and very comfortable. i would image that a couple winds behind the trigger would work just as well.
nice thing about this stuff is, it comes in all kinds of colors.