Afraid I've been slack & never tried too hard to learn to uphaul my 95ltre board ( weight + 32)..I managed a few times in flat water and found once I was up it was fairly stable 59cms wide( compared to a narrower board).The problem I have is how do you get to stand up to start with?
I find this is the stage where I give up..trying to get from lying over the board to standing up on it in the chop..Any tips?
It would be good to know I could uphaul it in case I'm out in 20kts + & it dies ( which it can often).
My board is a 110L (weight + 35) and I can uphaul a 7.4 no worries. When I get on the board I push with my arms to get me on the board on my knees (one knee either side of the mast foot). I then grab the uphaul rope with one arm and use the other arm to steady me (pushing against the board) while I stand up. Never had any problems getting up.
I've got no idea what I was doing but I'll give that a go.I know I steadied myself with the uphaul.
I can uphaul my 85L board (weight + 27) in flat water but wouldn't even try in chop unless I was desperate!
They key is not to wait until you're almost exhausted from trying to waterstart.
Your muscles will be weak and your control and balance is gone.
..probably why I've never persevered..
Main tip I would give is to push the mast as close to 90 degrees to the board as you can (and preferably board across the wind), then get to your feet quickly holding the uphaul.
A tip I got from a Simon Bornhoft course (www.windwise.net/?Itemid=1017) is to put the back foot in the front strap when uphauling. Helps with stability. I have uphauled an 80L acid with a 5.8 using this technique but it took a lot of trying (78kg).
At 108kgs, I tried to uphaul a 6.4 on my 109lt (weight +1) last week, got the sail up although was nearly knee-deep under water, but unluckily didn't have enough wind to move me, so sank. Got soooo, close, the trick is to set everything in the water first & move fast before you sink. If you can float, then it's more balance based technique.
If there was enough wind here, I shouldn't be even attempting it! 
