I also read that you can incorporate a wire within the luff, haul up the jib with the wire attached via spare jib halyard, attached the jib tack to the genoa roller furling tack and provide tension. This seems like a easy good method.
If you have roller furling, chances are that you have a 2nd slot in the headstay. You can hoist a 2nd jib in that slot and drop the #1. This is how a racing headsails are changed. But this begs the question that risk is induced by requiring someone to go forward to hoist/secure the sails. With a full crew it isn't an issue. With kids and short handed, it's a problem.
If your roller furling headsail has a foam luff, the shape shouldn't be that bad - certainly with kids aboard, performance is of secondary concern anyway. I wouldn't worry about loads on a partially furled genoa. A good sail can handle the load. Foam lufs are easy to retrofit by a sailmaker.
I have a similar dilemma, my 135% genoa's wind range is up to about 15-18kts. After that, she becomes unruly and the boat exceeds 25 deg of heel. So we reef the main, but the genoa is still a problem in 20-25 kts. So I'm thinking about buying a #2 (100-110%).