I’ve used VAR levers for decades. They work very well and I’ve used them with mountain bike tires. They are flexible. So much so that I am amazed that they have not broken. The flexibility is good and bad. They seem to hook on the bead a little better but there is less leverage. At times you are really bending it to mount the tire. It does fit easily in a medium under saddle bag.
I find the Kool Stop gives more leverage but staying hooked on the bead is sometimes a problem. It is not a hook, just a 90 degree shoulder. I’ve cut the handle down on mine to fit in a larger bag. I have only used the Kool Stop mounting mountain bike tires and you definitely have to hold the jack to the bead, which kind of renders the length of handle useless. It does work well. I think I like it better than the VAR.
John