In my experience I've found that Thunderheads like speeds well under 300 ft/sec. The addded guidance of a longer shaft with fletching way behind to give the ability to steer more leverage makes them work better in a vert bow. Try Slick Tricks, G5 Strikers, G5 Montecs and the 4 bladed Magnus Stingers. The Stingers and Strikers work well if you want to push the arrow faster.
Awshucks and I were talking the other day and we both agree that slowing down the arrow below 300 ft/sec is the ticket to better accuracy and forgiveness.