You could swap Metol in there but I don't know the amount. Your negs won't look the same though. Glycin usually gives a bit of a bump to the tones of an image.
You could also just omit the Glycin and develop longer, or increase the amount of Phenidone. Or use a Pyrocat variant.
That developer is really a Pyrocatechin developer. The Glycin and Phenidone just help it along.
I am sure someone will come along with more technical knowledge, but that is the gist of it.