I don't think I've seen an answer for it though. You just have to try it yourself. I've tried to put Tap Interval at both 100 and 500. I don't notice a difference at all, to be honest.
as I said in a previous post im a 99 percent sure that the hover interval is the length of time that something is activated when you just touch and HOLD not the time that it senses your finger but the time that you actually spend hovering on something
for example when you touch and hold a letter on the qwerty keyboard after a period of time it brings up a second set of letters based off that key.
swipe speed is being rumored around one person states that it could be that its how fast your finger has to swipe for it to be recognized and other people have stated that its how fast it recognizes your swipe..
Noone is 100 percent sure as of this moment as far as I know..
but the way the hover interval is worded it to me seems like it can mean nothing else.