I would set fees very low at this time. (transfer and market orders) As a sort of introductory rate. No sense in generating "high fee" press at this point.
As the price of BTS rises, the $ rate on fees will rise without doing or changing anything.
As the $ price of fees approaches the ideal rate (~$0.20) begin lowering the fee (in terms of BTS) to maintain this.
I think its important to reach as many people as possible right now, and fees should be so small as to not even be a factor. If you're selling the idea of lifetime member to someone the % savings is still the same and the idea of slowly reaching a target of 20 cents can be communicated.