On their website, they have a catalog of their "Professional" products. Page 16 lists the compounds. They sell pads also. They also have a toll-free number. You could tell them what you are using now and ask them what they have closest to that. Just between you and me, after the 1500 grit, I think you should consider sanding again with a finer grit. 1500 seems pretty fine but polishing out 2500 grit sanding scratches is way easier and faster.
https://www.meguiars.com/sites/default/files/pdf/professional-catalog.pdf