Yes, tackle is called a "snotter" traditionally I think.
Sheets to the transom corners can have a great deal of vang effect, but then you have to tend them. The sprit boom should do all that is required there, particularly if it has a bit of rake, or the tack is below the boom.
As Semi said, two sheets to the stern quarters. Lets you lock the mizzen wherever you want it, and doesn't need tending while tacking (once trimmed) or gybing. Backing is something you want to do occasionally, on a cruising boat anything that wants doing occasionally but requires rigging...
A practical consideration: you need to be able to get to the mizzen clew from time to time. Now on this one you may be able to unship the sprit boom to take care of that. Mine was drawn with the mizzen overhanging too far to reach. Fortunately the first couple of months were spent in a berth...
My mizzen is about 7" dia at the partners, tapering to about 3" at the truck (wall thickness tapers too). Tube is about 38' long. It was intended to support a 260 sq ft mizzen and a 290 sq ft staysail.
It is quite a useful sail.
You could easily make the mizzen unstayed (or maybe it is already, can't really tell). No rigging to be dealing with all around the cockpit. My mizzen is more that twice that big and much taller, the tube weighs a little over 100 lbs. Two people literally could pick it up and stick it in the hole.