We didn't mention what you are wearing. I have the extra halyard tied with a bowline to my climbing harness. The lifting halyard is tied with a bowline to the boson's chair. The least skilled helper pulls the slack out of the safety halyard through a closed clutch as I'm lifted in the boson's chair.
When up, I use a long climbing sling to take the load off the lifting halyard.
FWIW, I was 160 lbs and went up my E23 (fin keel) mast with no tipping issues.
Mark