Wrist issues not withstanding, I agree with some of other posters that it will be easier to generate the spin with an extreme/strong/modified Eastern grip than with a pure E. grip. With a pure E. you really have to lay your wrist back a lot to be able to pronate your forearm and generate a good topspin swing path.
I suspect that this is why some players who use an E. grip also have a straight-ish arm at contact. The straight arm would tend to reduce the amount that you have to layback your wrist. But consistently hitting with a straight arm has its own set of difficulties. Something around SW is a really good compromise for wrist position, generating the swing path for topspin, but still being able to flatten out shots when desired.
When I started hitting a modern fh two years ago my fh grip was fairly centered between E and SW. It's migrated to be darn close to SW, although I don't think it's quite all the way there. That type of grip migration is pretty common from what I've heard. To a certain extent I've just let my body tell me what it wanted to do and went with it. I'm big on analytics, but you do need to feel it too. When your hitting feel is all you have, so it's gotta feel good. The results are working for me.