Spinnaker or Cruising Chute and Mizzen Staysail

You might consider having a mizzen staysail made for you. They are very simple, light sails, so reasonably priced, we had Crusader Sails (in Dorset) make one for us for 325 GBP in 2014.
The nominal size per Camper and Nicholsons is Luff 23.50’ x Leach 20.50’ x Foot 23.50’ which is what we had made. I sometimes think the luff should be 1′ shorter, but am quite happy to have the extra sail area.
The staysail is a blast to sail, easy to raise and douse, and really helps make speed in light winds. We can use it from an apparent wind angle of around 80 degs, down to about 120 or 130.
We did have one problem this summer, when I did not pay enough attention to the lead of the sheet, which goes through a block on the end of the mizzen boom. The wind was around 12+ knots apparent (the upper limit for the sail) and I didn’t notice the sheet rested against a shroud – it chafed through, leading to quite a bit of excitement!

We went with the light Dacron and are happy with it. We’re sailing in the tropics now, and dacron should last longer than nylon, and also as you note, allows use in slightly higher wind speeds. It is also more traditional looking than a flashy colored nylon!
One disadvantage of dacron is that it does not pack in a bag quite so easily.
Finally, I had an old “ChuteScoop” sock that had been used for an asymmetric we once had and I have set that up for the staysail. The trick is instead of having the scoop cover the sail from the head down like you would for a spinnaker, you have the scoop start at the tack, meaning that when the sail is deployed and sailing, the scoop is bundled up down at the tack by the windward chain plate. Then, to douse the sail, I just release the halyard and hold the bitter end in my hand keeping tension on it, walk forward to the sock, grab it and then walk back pulling the sock over the sail, letting down the halyard as needed. Of course, you could just use a rope on the mouth of the scoop and pull it aft so you would not have to walk forward and back.