No loss at all in detail from boiling.
Like you said, you should try it just for ****s and giggles!
After reading this thread I decided to give the boiling method a go.
I'm new to sculpting and had recently sculpted a baseball hat onto my David Dunn/Bruce Willis sculpt for my Unbreakable custom.
The head was cheap - $35 - and it comes painted. It's made of some sort of plastic so throwing this thing in the oven wasn't an option:
I filled a large pot with water and inserted a strainer type thing that had a post in the middle. I covered the post with tin foil and inserted the post in the base of the sculpt:
I turned on the oven and got the water boiling. After 25 minutes I turned off the oven and let it stand for 2 hrs. After removing the sculpt from the water, I dried it and inspected: No loss in detail, and the sculpey was rock solid.
However, once I attempted to mount the head back on the body, the brim snapped off.
That hat was certainly not, unbreakable.
I should have figured that at this scale, it wouldn't be able to withstand much.
Here is a shot after I started to remove the hat:
Still, the method worked. I have to decide if I will attempt to resculpt the hat or possibly use an actual 1/6 scale hat if I can find one. For now, he remains hood up: