Also, how are you edging in for a double up? Some of the pros don't even edge in very hard. They time it by slowly going over the first wake, then speed up as the go over the second wake, then by the time they hit the 3rd wake their speed is just right.
I used to fly into double-ups and either miss them or totally get thrown off because I was coming in to fast.
I would say once you get used to them, you can start coming in at a faster pace.
my two cents.