I like the electronic digital angle gauges. Rockler sells them. It can be a real problem when the blade does not protrude a sufficient distance. I have found that you can do the best you can by adjusting the blade and then make a test cut in thick wood. Measure the angle on the wood, not the saw blade. Go back and forth to dial it in. This isn't the ideal situation, but it works. The gauge gives you precision (decimal point readout), accuracy (against know machine standards) and repeatability when you test across multiple pieces. Let's face it, there probably are some inherent limitations with the TS55 for this use.
The table saw may or may not be better for this use. Another point -- For segmented bowl turnings, look at the table saw add ons sold by Jerry Cole at Inline Industries. He has published a new book and DVD on using the tables --- book is called "Polygons". He is a fixture at all of the Woodworking shows in the US.
Also a Kapex miter saw is very useful for cutting some small pieces (I realize your question is on bevels, not cutting pieces to length) --- not only because of it's accuracy, but the fact that you can dial the speed way down and the pieces don't fly around the shop like unguided missiles. Many do not know of the variable speed feature on the Kapex --- it handles the most delicate moldings very gently
