TBH the boots on the ground answer here is to ride bikes.
If you are already a cyclist and have ridden you should be at least mildly aware of what bikes you liked and for what reasons. From that you could extrapolate geometry and make predictions on what might work out, but in my mind you are setting a trap buying an off the shelf bike without having ridden the exact size and in many cases the exact model you want. I would concede that an experienced cyclist and frame builder are not subject.