Here are my comments on the draft paper; thanks, I now know very well what you are up to. General notes would be that the paper could be more careful with language. `Beta regulates' ... is not really correct, but `The feedback regulation path whose intensity is controlled by beta ...' is more correct but rather unwieldy. In this paper, I think context rescues it and we don't need to worry much. But for your PhD write-up, we should be very careful and correct about this kind of thing.

I just can't get on with `Track Changes' at all; I hate it. So my comments are all done by hand in red.

It is not clear to me from teh paper what biological evidence there is or isn't for the various feedback dependencies here. This is maybe not needed for the paper, but it would be good to find any such evidence. If there is no evidence in an particular case, then we need to know whether or not it seems plausible to suggest it in the first place.

For PhD purposes, it seems to me that a straightforward and useful next step would be to do a similar set of experiments, but homed in on the values that hit the experimental data. E.g. fix tau, fix delta at unregulated, and choose suitable sets of new values to explore for the rest.