I am also using a grigri with a climbing harness. I use use a bosun's chair, the climbing harness is backup. A pair of asenders with foot loops. Second independent line with a prusiks
knot.
I trust my halyards, as I spliced them and sew and whip the splice. But attach both as a
safety precaution. I use a climbing rope to protect my halyards from the grigri and ascender teeth. I have also found the devices
work smoother with climbing rope.
I don't like the climbing harness. It works but it's painful after a while. I found tree climbing harnesses recently, they are padded and have more support. They're made for working all day while hanging from the tree. They're expensive, but will be my next
purchase when I climb the
mast next. A lot of tree climber
gear and techniques apply to mast climbing, more than rock climbing gear.
I don't trust other people to
winch me to the top of the mast. I have done it, but I don't like it. To many things can go wrong especially when they switch to descent. I prefer having the control of ascending and descending in my own hands. If something messes up it's my fault only.