I embarked on the same journey around 25 years ago. It worked out okay, but it took a long time; I guess I didn't have a decent embouchure. The suggestion of a Schilke 24 mouthpiece isn't bad, in theory, but I'd modify it to suggest that you play the smallest trumpet mouthpiece you can. I did play a Schilke 24 for a number of years, because it was the only thing I could fit my upper lip inside of and still get a buzz. Any smaller and I had to play "in the red." Over the course of quite a few years I downsized from the 24 to a Bach 1, then to a Bach 1C, then to a Bach 2.5C, then to a 3C. At that point I'd learned to roll my lips in enough to play smaller mouthpieces and could try them out and learn their strengths and weaknesses. It doesn't matter what mouthpiece I've ended up on -- if you follow it through, your own journey will lead you to the right size for you, for the playing you do.