The S-84 is not massive, if that's what you mean by "beast" it's certainly not drainpipe. I have a few of them. The top is aluminum, and the shaft is CrMo, with very thin walls, way less than 1 mm. The S-83 is also not as light as a Thomson Masterpiece, which is lighter than some carbon posts. If you find some composite posts with more setback than the S-83, I'd like to know.

I would recommend getting a fit, but I don't know how to pick a good fitter. The fit systems put together by Specialized seem to be pretty good.

But you can go it alone if you're careful. If you're able to revise saddle positioning to relieve knee and perineal pain, for me that's the basis of staying safe.