How big is your fuel tank? 15% of 30 is 4.5 gallons.
JPA? Do you mean JP8? JP8 with some 2 cycle oil (marine grade, preferably) will run great in these motors. I know an aircraft mechanic who has been running reclaimed JP8 in his truck for years.
'02 F250 7.3 Auto Extended Cab Long Box 240+k Miles No Mods