Would I be able to use my Treesuit as part of a Custom SitDrag?
If you have a treesuit, you don't need a sitdrag.
You need:
A knife/scissors.
A bridge of your choice.
Buy or fashion a belt that you trust, preferably with rings built in or a way to sew (non-life supporting) thru two layers of seat belt or webbing.
I cut away the rope from the webbing. And I removed the belt. So i was left with the seat, the back support and the webbing straps that come off the bottom of the seat.
I use those straps to connect my bridge to.
The only 'tricky' part is the Linemans belt which is also how you keep the back of the Treesuit 'up' on your back...
I used a 2" seat belt style belt that I had from a fall arrest that came free with an old stand. I simply stitched a second piece of seat belt on the inside of each side of that 2" belt. I put climbing rated carabiners in between those layers, I'm sure to connect to the TMA approved belt - my sewing just holds the carabiner from sliding forward on the main belt.
This becomes my Linemans belt for climbing. Then at height can hook up my bridge to the original factory webbing coming off the seat.
I also added some of the soft, sticky camo tape that comes with a summit climbing stand (i will pay for any that others have around), to the front where the seat will hit the tree. Save wear on the treesuit and silence its contact point with the tree.