Hey Andy, thanks for questions. Please see this link which includes DCF calculation and inputs we used. You can see that $28M used in presentation was just one example used from range [7, 35] that we obtained using different inputs. Some inputs are very subjective and hard to forecast and this is why we believe community should crowdsource them to obtain reasonable estimate for MKR dilution capacity (you can either decide for one from range of inputs we used or simply try using different ones by changing numbers in input cells)
Regarding your question about MKR governance premium: the idea was that when MKR has 0 rates (as currently) and potentially no cashflows from penalty fees, DCF would in such case yield $0 MKR dilution capacity, which certainly isn’t correct. This is because we believe there is still some substantial value in MKR as governance token, despite scenario of having no cashflows. We call this value governance premium that is added on top of value obtained from DCF. The issue here of course is that there is no good model yet (to my knowledge, although this methodology may be interesting) to value governance premium and therefore we used some intuitive range.
If you have any further questions please let us know.
P.S. If you are going to play with different inputs, please make yourself a copy of sheets file. Feedbacks are very welcome.