Tony,
what you have thought out there how to reef your mizzen probably works.
But I would not do it. As you -as I- have a luff pocket mizzen, rolling the mizzen around the mast destroys the main advantage of the luff pocket, the ideal aerodynamic profile and lift of the sail. You would reduce sail area indeed, but you diminish what the sail is there for to give you, forward pull. Generally speaking you end up with 'heel without pull', not a comfortable situation when you really would want to move on out of it.
If your original mizzen is too tall and large for single handing in a blow, I think it should be made smaller, instead of being made reefable. In a blow you have your hands full with reefing and unreefing the mainsail plus maintaining steering, having to reef an additional sail as well seems a bit much to me.
I today have two mizzens. The original big one for fun sailing with able crew, a shorter and smaller one for staying in control when going out all by myself or with relaxed crew. These simple luff-pocket mizzens are tiny sails by any sailmakers standards, so they are inexpensive to make and buy. To shorten the mizzen mast it just takes a second shorter top half standard windsurfer mast which may be slid onto the lower half, replacing the original longer standard top half, and vice versa.
Your weather helm, I understand you are not really using your jib, so this must be expected.
A smaller mizzen plus adjusting your lee board can improve it, but full balance in a blow can only be achieved with using a jib.
Claus
In my book the mizzen -in connection with the jib- should be your fall-back
Your mizzen appears to be too big and tall in the first place