X and Y pay 200%
X list is only for your base and you can refuse the trip when offered
Y list is for any location Spirit currently has service, you can report in 3 hours or less, and you can not refuse an assignment. Basically if you answer the phone on a Y list, you’re going. That has caused issues with pilots being assigned Y list trips for a longer duration than what they showed available for when signing up for Y list trips

The X list pilot gets any and all DH pay since the trips start and end at their domicile

The Y list trip is different. If you’re a MCO pilot and Y list for TPA, your trip will show a virtual DH to start showing MCO-TPA (for crew tracking) and 0 credit. The end of a trip will have a DH or operational trip back to MCO, in which the pilot is paid for. So the pilot has the option to take the DH back to MCO and get back to TPA on their own or self release the leg before and JS back to TPA.
Y list trips can be productive because you’ll see a lot of 1 leg, overnight, and DH back the next day to base. So the pilot does the 1 leg, gets released, and catches the next flight home, and it’s 20 hours minimum for a day of work.