I have only ridden two KX5's and I can start them both sitting down on the first or second kick everytime. I suggest really finding the correct timing of when to give your own bike a full kick. Generally speaking, get it on the down stroke of the piston just after TDC. I personally give three small slow 1/4 rotations of the kicker after TDC push-over and then a nice 3/4 stroke kick sitting down... hot or cold.
If you are getting wear on your boot soles, it's probably from the foot pegs more than the kicker I would imagine. I can't see the aluminum kicker tearing up the boot soles, unless you are kicking the crap outta your bike every start-up.
I think any Alpinestar is a great boot, Tech5,8,10's. Of course every one is different and the only way to find what fits you best is to hit a large retail shop and try some on.
Oh yeah, a boot under $200 new is probably not a great performer. Somehow the old saying fits again "you get what you pay for"
Sly