The reason I usually recommend RV anti-freeze is that it's a cheap experiment, and if it turns out you need new tires as well, you're not out too much dough. If I had a RimGaurd dealer closer to me, sure, that's what I would use.I'd recommend Rim Guard instead of RV antifreeze. It weighs 11# gal vs 8# for the anti-freeze, and with smaller tires like that the 3# extra per gal will make a difference.
The JD dealer that did the tires for my Bolens 1886 only charged something like 3.60 a gal for the Rim Guard, and that included installation. My 26-12-12s hold 10 gal each, so it added a good amount of weight.
As for turfs vs Ags, I'd recommend that you look at some ATV tires. There are a LOT of options for how 'aggressive' a tire you can get. I went with a pretty aggressive tread by going with CST ANCLA tires, but I wanted that for the 1886 as it has a FEL, and I'll be working in some fairly soft ground with it.
You could also investigate some of the HDAP tires. They are basically aggressive turfs.
If your stick tire is an 8x16, then I would guess your rims are 6x16, or 6.5x16. What is going to mess with you is overall height. Your stock tire should be approx 32" tall mounted. The most common sized mud tire which is 32" tall is a 32x11.50-16. That is going to look quite ballooned on your narrow rims. I suppose you could change rims, but that just complicates the situation.I would consider an aggresive 16" auto tire, but other then the 16 inch part what size (s) can I use. By the way, I never thought of this