VFD recommendations for Bridgeport W/gecko 201's (was Boss 3)

I'm looking at the inverters from WWW.DRIVESWAREHOUSE.COM.
Unfortenetly, thier tech department cannot help too much....

the machine is an older Bridgeport Series 1 with a Boss 3 controller.
I just ordered 3 Gecko 201s yesterday for the machine with hopes of
using as much of the existing Boss 3 controller and powersupplies as
possible.

for the VFD, about all I know to look for is 230v single phase IN and
230v 3 phase OUT and I'm guessing 2hp....would it hurt to spec a
slightly higher hp VFD such as 5hp for my mill??

thanks,