Sailing with Genny only
I have a Catalina 30, Jeanneau 34 and an Elite 32. All three have masthead rigs with 135 Gennys. I have sailed all three boats in 25 plus with Genny only, provided you're on a reach. Rolled the Genny in by 1/3 and flew prefectly balanced at 6 plus kts, with no weather helm. Your Morgan is heavier though, and might need some more sail power. All boats handle different, so this is just my experience.
I prefer sailing in heavy winds with Genny alone as it is easy to reef and put away in case of emergency and building winds. Also means you don't have to go up on deck which is always a good thing in heavy seas. As all my boats have lazy jack stack packs, it makes dropping the main a lot more difficult in adverse conditions (you have to point DIRECTLY into wind or sail gets caught on lazy jacks). Thus my prefernce for genny only.
Ideally a reefed main and reefed headsail will give you your best balance, especially if beating, but this is a small sacrifice for safty. A genny is easier to pop out if you get a big gust.
Windsong Sailing Charters