IMO, fit is not a one time thing but changes with fitness, experience, objectives, compensation for injuries, etc.,
so being able to DIY is good. Rollers have been good for me- ride for a bit, make adjustment, ride for a bit, then try it out on the road.
Steve Hogg website gives lots to consider- arch support, cleat position, saddle issues, and more.
Lots of YouTube videos to sift through- some more useful than others.