thats why i would have a lower base price for everyone, thenfirst class passengers still get their seats(business's who pay for it would look at you more because of the cheaper seats so more business there) and coach passengers would want to go with ya because of the cheaper cost for the pleasure of first class seating.
need to work out, how many seats you'd get in, i'd imagine at most 50 first class seats or 80 business, in a DC10 maybe a few more. on a flight of say 3 hours or less, you could charge $350 a seat, maybe a little more than southwest jetblue and song but your getting first class,
3 to 5 hours $600 a seat and then 5 to 10 hours $800. those figures should make you a profit and should with the right marketing bring in all ranges of customers.