The Gen II will be easy. I DO HATE doing it to a Gen I with 5 hoses. Sean saved my bacon (more than once) when I had trouble purging the air from one of ours...check your "radiator cap" on top of the pressure bottle to be SURE that it works properly...i.e. holds pressure and pops off at correct pressure. I would also say that it is important to FULLY seat the hoses AND to tighten the clamps down WELL. I have always gone "lightly" on silicone, so I was NOT surprised to see the lower hose slip back a little after a few run cycles. Check for hose fit and watch for any leaks initially...and keep a close eye on the overflow bottle in the fascia.
P.S. cleaning sludge from that bottle can be a bear.
P.S. cleaning sludge from that bottle can be a bear.