I am bored so...
Assume you have a harness...?

Assume you have chicken loop attached to hook on same...?


The bulk of your load should be on the harness.

If it is windy and you are getting light on the toes walking up the beach back to base (with the kite in the air) de-power it.
If the bulk of your time is on the water and you are getting blisters from this, try moving your hands from the end to the middle of the bar and back every 30 or so seconds - i.e. break the grip.
My slingy is a few years old (assume the modern bar setup includes a stopper), I use the stopper to set the bar when I want to cruise. Then can use one hand to steer i.e the bar is light to hold on to. Try it.
Your blisters remind me of rowing - at the beginning of the season. Metho' dried out blister, also used formaldehyde fires up the nerve endings with either[}:)]
Realistically - the brand of bar (/kite) has no bearing on that problem. Was going to say more likely a life style issue - got to get out there and be more manual... But I noticed you like to also surf ski, wake board etc etc - both should have toughened you hands - bottom line - relax (specially hands) when kiting.
AP