Which flywheel?

Hi
I have just purchased a pk125ets race crank,i want to use pk50 electronic ignition (i believe it will fit?)but what flywheel do i need the sip catalogue says a standard pk one will fit,but the taper on the ets crank is bigger,i`ve read that the hp4 flywheel is good but also the pk flywheel is quite light
HELP!!!
Thanks Adrian[:roll:]

the hp4 is ok if you dont mind an erratic tickover, not brilliant lights and setting it up with a timing gun. dont know which taper is correct sorry.