OK so here is the progress I have made with getting phantasy star on to a megadrive/genesis cartridge.
First I build a pin converter from master system 50pin to Megadrive 64pin. This works very well with most master system games.
Then I put phantasy star on a 32pin 27c040 EPROM and got it working on a monopoly PCB with some extra wiring.
This monopoly phantasy star works on master system, game gear with converter and Megadrive with my homemade pin converter.
All I have to do is put this mess on a pcb.
As far as setting up stack pointer phantasy star doesn't need it but I bought an official power base converter anyway so I can dump the 315-5342 for use later on.