Biggest issue I think you’ll find with the predator is that you’ll need to use large carabiners for the Garda hitch. Other obvious problems are bulk and weight.
I used about 80ft of rope last year and was able to get in every tree I wanted. Sure there are cases where you could run out of rope but remember that’s going to be at crotches around 38’ foot or so.
One concern with smaller ropes outside of strength would be smaller diameter means less hitch touching the climbing rope, when you get down to 8mm main and 6mm cord that can make a significant difference in how many wraps you may need for a given hitch to properly hold the additional weight. I think you will find JRBs new hitch variation a good fit if you do decide to go to 8mm for several reasons. The doubled over rope is one of the reasons you can use such small diameter rope so well.
A couple of points with JRB and JRB hitch from my perspective.
1. remember since you’re climbing two ropes, each hitch is only holding half your weight. So imagine a 135 lb person climbing each side, that’s not much at all!
2. you can add or remove wraps on the JRB hitch as needed to get your optimal friction. John shows how to tie these variations in his videos.
3. The way the non-binding hitch variation is routed you have two ends both in basket per side. So whatever your 6mm line is rated to is times 4 since there are four lines.
4. The non-binding variation should not bind on you regardless of your weight. This can be a problem for basic hitches since more weight means the harder the hitch grabs. I think this concern is significantly mitigated because of the non binding variation hitch and because your weight is shared by the two ends of the doubles over rope.
I have been doing SRT and DRT for a couple years off 75’ and on occasion wished I had more rope. I was thinking with RescTech I would go 100’ with that still being sub 3#.
I would also just start out with the JRB ascender hitch. May as well start with the latest and greatest. I assume the non-binding one you refer to is the video titled non-jamming JRB ascender?
John, curious what your thoughts are on a “big ole boy” swinging from 8mm RescTech?