quick answer: find a boot that fits your foot well and get the cuff lowered?
long answer: find a boot that fits your foot well, AND fits your calf. I've had VERY good luck with the technica cochise (moving the buckles) and I think the new magnum will be even better. Also, get a smaller boot then you think. This will help hold your foot in place better, AND will be lower to start wtih on your calf. (size 28 is taller then size 24) so less of your calf is in the boot to start with .
also a heel lift might help