Imo you may learn to shoot better faster shooting off a shelf. It places the arrow closer to the knuckle so things seem to aim more natural. On the sideplate I place a piece of matchstick so less contact occurs.
The small feather thing may work, I've never shot anything but 5" helical. It stabilizes the best typically n with little ways to adjust its best to help the arrow out.
Nock point height may need to be adjusted so shoot through paper to get a read