Reefing is a genoa is not...
as simple as one might think. If properly cut and fitted to an appropriately sized furling system, either size sail you have suggested will furl properly. Its the reefing that is the wild card. You can't really reef down a big foresail very much. Depending on who you talk to, I have heard you can reef a genny from 10-20% and still retain enough sailshape and strength to make it worthwhile. I was given this somewhat rude awakening by my local sailmaker when I told him I wanted a 150% genny that I could reef down to standard 100% jib. Choose the size of your reefing headsail based on the strength of the prevailing winds in your area and your preferences for how much sail you like to carry. I decided to have my 100% jib put on the furler. My 150% genny has a bolt rope its leading edge, so I just hoist it with the now spare jib halyard.