I used the Gel Poly on some flat work. It went on easily, with some waste (excess that I had to remove as I leveled it out).
I put on two coats with some 0000 wool polishing in between.
These were shelves, and are now under 30 or 40 pounds of jewelry beads my wife uses.
The finish is easy to do, and seemed to be fairly "sturdy".
I have made the mental note that when I do more flat work, I will probably use the gel poly as the finish. I have no experience with putting it on a pen, but my first thought would be that swirls will be really easy to create.
I think I would put the poly on a stationary blank (not turning), steel wool a bit between 3 or 4 or 5 coats. I think it is definitely worth a try.
My guess is that once one begins "the trial", a fair and victorious finish process can be developed. If you go for it (which I would advise), let us know how it goes. I won't be in position to try until my 'honey-dos' are done!