mrcallow, you can probably do the same job by using D-76 stock solution to dilute the Dektol, then add the ascorbic acid and additional soda, but I'd surely want to test it before committing anything important. The borax in D-76 might lower the pH of the super soup and slow the activity, but in general HC-110 Dilution B was made to work like D-76 stock solution. And you might see increased fog, since D-76 has less anti-fogging properties than HC-110; a light dose of BZT might help, but could also reduce activity and leave you with thin negatives.
In my case, I didn't get to really test, because I was trying to save a negative accidentally exposed through the base (and, fortunately, discovered when unloading the holder rather than when the negative came out invisibly thin). I did something even better: got lucky.
However, since you're probably all done by now, how did it come out with whatever you tried?