That's not really what I would call dry as a bone, not from how they appear to me at least.
I don't know if you left them for a few more weeks after that pic, but they would have dried and shrank a lot more than that as they lose all moisture over the course of a few weeks to several weeks. They eventually just become like desicated shrivelled husks. I dont think they loose too much potency either after being dried. I did that most times. I think I only once ate them just after I'd picked them - the first time.
I never tried to accelarate the drying on radiators or anything like that. I just left them on newspaper on top of my cupboard. (In my bedroom in my parents house. I think they tended to stay out of my room on the whole by that stage, thank God, as there would have been absolute hell to pay if they'd ever found those.

)