These are not 2 opposing goals which need to be balanced, they are the same goal! If you can satisfy existing holders then you will also get the new investors, because the value goes up which attracts more people. If you can't satisfy holders or increase the value of the coin then why would anyone want to become a holder?
The thing is that we already know, because the coin and similar inflation model has been out for a while, that the current model can do neither. Nobody wants to buy, and 1 btc in the buy order list is effectively a collapsed coin. The fact that the market hasn't picked up since the announcement means nobody has confidence or wants to buy into this model. You may say it needs marketing, but if none of the existing people following it think it's worth buying then you're not likely to find new ones either.
I don't understand why 20% a month is “not too much inflation”, if you can help us understand this then maybe we can give the idea some support. Can you give examples of any other coins which have been successful with similar levels of long term inflation?
By that I mean in the modern coin world after the rise of PoS.