I started on a Bach 7C until Bernard Adelstein told me to switch to a 1.5C. Bernard told me recently that he still plays his Bach C trumpet with his 1C mpc. A bigger mpc for smaller trumpets make the horn sound better, IMO.
One point of interest is that Bernard's lips are not big but rather thin; so, the idea of bigger mpcs for bigger lips does not always fit the scheme of things.
If you want to make the 1C feel more comfortable, put a DW4FL into your horn for awhile……..ouch!!