The only way I would have attempted it would be on a full cylinder and even then let your partner hold the other end of a dive reel so you can keep tabs on where you are at. However at that depth, Im not sure even with doing that it would help too much, but certainly for sure better than not having no reel at all. Even then this would be controversial for some.
Your decision to call the dive may have proved to be a good decision. Lets take another look why:
Knowing your stature and small frame, on a good day I would assume your SAC rate is next to nothing as you have done proved that to me however now you just task loaded yourself with multiple issues which will increase your SAC rate quite a bit.
1. Solo diving how comfortable are you at doing this?
2. Solo diving in a dark, cold, limited vis environment.
3. Using another buddys mask which may not conform to your facial features as needed for a safe dive.
4. Familiarization with how to do a search pattern with limited vis
5. Tired, stressed etc from having previously done two dives, not to mention nitrogen loading from those dives.
Since you were diving with your Alu 80s you have a tank baseline of 2.67 cubic feet of gas per 100 PSI. (IIRC so check my math) You mentioned 1500 remaining PSI of gas which would have given you just over 40 cubic feet (but you already knew that since its half your supply right?)
Not knowing your previous profile, I cant plug those numbers in to see what your deco obligations would be (in your case safety stops) however even had this been your first dive you with a guessing SAC of 0.7 you would need around 44-45cfg. Below is the profile with a 10 minute BT.
Depth Time O2 He PPO2 Ceil 120 10 21 0 0.98 40 Size Rated Fill O2 He MOD Res Cu Ft 80 3000 3000 21 0 187.00 0 44 Depth Time O2 He Start End PPO2 Gas Gas Reqd GF% MVal% CNS% OTU 120 10 21 0 1 10 0.98 0.70 40 0 15 3 8.41 40 1 21 0 12 13 0.47 0.70 1 20 54 4 9.59 30 1 21 0 13 14 0.40 0.70 1 52 59 4 9.59 20 1 21 0 14 15 0.34 0.70 1 69 65 4 9.59 10 1 21 0 15 16 0.28 0.70 1 85 72 4 9.59 0 17 85 82 4 9.59
So, long story short; good decision on your part for sticking to your gut instinct. Its only expected that everyone donate something to the quarry at some point in their diving career. I have a snorkel somewhere along the bottom what better place for it!
Safe diving.
Kenny
P.S. The forum program seems to wrap the text......In this case the profile is all gibberish. Sorry