Two years self taught and still fighting the same shoulder and bust fit, is a paid class worth it or is that money better spent on fabric

Cheaper middle option before you book anything: get a friend to take four photographs of you wearing the muslin, front, back and both sides, arms down, no posing. Fit problems are obvious in a photograph and invisible in a mirror because you unconsciously adjust while you look. Four muslins in a row means you are diagnosing blind, and the camera fixes that for free.

The general six week course will teach you what you already know and the one day fitting workshop is the one you want, assuming it is genuinely hands on with your own body rather than a demonstration on a dress form. What you are describing sounds like a full bust adjustment plus possibly a forward shoulder, and both are extremely hard to diagnose from inside the garment because you cannot see your own back. Ninety pounds to have someone pin it on you once and explain what they are seeing is the best value in this hobby.

I paid for a two day fitting course in 2023 and I would do it again, but I want to be honest about what it did. It did not teach me to fit, it taught me what a good fit feels like on my own body, which I had genuinely never experienced. Everything after that was me making the adjustments myself with a reference point I did not have before. If you go in expecting a technique you will be disappointed, and if you go in for the reference point it is worth every penny.

Mild disagreement with everyone recommending the workshop. If your budget is one thing, I would spend it on a made to measure block or a pattern drafted to your measurements instead, and then use that block to check every commercial pattern before you cut. It solves the same problem permanently rather than one garment at a time, and around here it costs about the same as the six week course.

Whatever you choose, stop making full muslins in cheap calico. Cheap calico behaves nothing like the fabric you will use, so you are fitting a garment that will never exist. Make the bodice only, in something with a similar weight and drape to your intended fabric, and you will learn more in one afternoon than in four muslins.