So, not a commercial mix, but called TDLC-103. 1g metol, 5g soduim sulfite (pinch of this in prior to metol first), 10g sodium bicarbonate per litre.
5g/l sodium sulfite as a stop bath is recommended with this. Not sure why; I have not experimented without it.

Calibrated times at night by laying a Stouffer TP120 6x6cm 31 step 1/3 step step wedge on top of an inverted spare omega dichoric head under a copy camera. The head was dialled to 100C +30M to simulate daylight adn a DB diffuser was used and step wedge was masked off to cut down on possible flare. Shot with room lights off. Metered with a spot meter onto the 12th step to try to meter what I hoped would be middle grey. Took meter reading and factored in 2 stops for the bellows factor of the lens setting on the copy camera, a Polarid MP3. So exposure was f/5.6 1S as a first trial at EI25.

Shot 4 negatives, and put all in same tank of developer. Pulled hangers and set into stop tank as timer ran. Ended up with data for 20C temps of times of 5, 8, 11, and 16 minutes, 30" agitation intervals.

HD plots showed that for EI 25, I only got density out to 15 1/3 steps for the longest development time, and slope was steeper than standard development.

So next round was EI 12, and I developed for 8, 10, 12.5, 16 and 20', again agitiate every 30". Much better data from this round. Exposures out to 20-22 steps.

I use a R-18b Kodak development dial for all of my work. It comes from a mid 80's darkroom datatguide, and is handy for translating results to a standard 20C when things are not quite 20C. I have extended it's range to work out at 38C for E-6 as well.