Nitroglycerin cream gave me pretty bad headaches but did seem to work the one day I climbed after taking it, but it was a rather mild-day as far as CO rockies alpine days go so with n=1 it's hard to have a definitive conclusion.
I also did the Murray's Method treatment last winter. A little back story: my biggest problem is that my hands sweat excessively on approaches so I'm dealing with a evaporative cooling issue that still makes my hands go numb as soon as I slow down, the blood stops flowing and I start touching cold metal crampons/screws etc. With that said, after having done Murray's my hands rarely go numb skiing resort days where my hands aren't sweaty. I've skied a couple of really cold days here in CO this winter and haven't had the problems I used to.
Going through the whole Murray's method process is a pain though. I did the sequence 3-5 times a day, every other day, until I had done 60 cycles. The biggest problem I had was getting my body to be cold outside. I generally run very warm so even here in CO in Jan/Feb without a shirt on and with a fan blowing on me, I had to sit outside for 20+ minutes to get the necessary chill - I can't imagine how long it would take in the mild PNW without access to a walk-in freezer.
I also saw an acupuncturist at the same time I was doing Murray's method. I had two accupuncture sessions and then he gave me a Chinese herb concoction. I'm guessing the effects of that were more temporary than Murray's so I do attribute the benefits I've seen to Murray's and not the accupuncture.
Good luck though. After five years of working on this issue, I've finally got my kit and process down to where I only get numb hands occasionally. When they do go numb now however, they seem to come back a lot more quickly than they used to.