I never, never, ever, anymore, use a short starter with a wooden peg. Back in the mid 70's one cold morning as I was loading a deer load, my hickory peg split and I sliced my hand open on the front sight. I had to start the ball with a hammer and wrap my hand in cloth as I was 50 miles from home but I hunted anyway.
Which brings me to the rest of the story...
The next week I replaced the wooden peg with a cutoff .35 Marlin case, deprimed. Since I didn't have a round cutter the right size I just chamfered the primer pocket with the closest drill I could find. Everytime I started a ball it left a perfect "cut" ring in the top of the ball about 1/3 down. And since I was casting balls of pure soft lead the cut was very obvious. This bothered me for awhile but at the range I could see no loss of accuracy, even off a bench at 100 yards. The next spring I placed 3rd in the 50 yard offhand match at the Southeastern Regionals. I have never again worried about the little ring.
I still have this short starter and still use it occasionally, like when loading from a block as the peg is a little longer.
If anyone has ever seen the Hershal House video of building a Kentucky Rifle then notice at the end where he shoots the rifle he just built. He doesn't use a short starter or a coned barrel. He places the ball on the patch then takes out his patch knife and RAPS it a good one which starts the ball, cuts off the patch then sheaths his knife. Now if anything will, then the end of knife will deform a lead ball. But take a close look at the offhand group he shoots then decide how much affect the deformation has on bullet flight.
I agree, I think the leather cushion is a solution to a problem that doesn't exist.