@mouse even though it hasnt been common at this point for me..I really like the alternate tuning sound.  You should investigate them and see what you like.  I have one fiddle with helicores that sounds awesome tuned down GdGd and DDad.  It would be nice if others on here that have been to places like clifftop or other events to share what theyve found in the way of jams and how alternate tunings are used.  usually what happens is a jam will stay in a key for a while then switch.  it makes it easier for banjos so ive been told.  guitars just capo.  durning that key switch ive never seen alot of retuning on the fiddles.  Im sure its more common than im making it sound and the sound it gives is what i think alot associate with the old timey fiddle sound.   but with you being more focused on solo play you dont have all that to worry about.  Easier to experiment and spend time on it and not worry about learning things in a way that transfers back to a particular group of jam buddies.  

I think trying to categorize too much or expecting past conversations to suffice for someones post of today..whenver TODAY may be is challenging.  im more for just talk, do your best to find a similar section and roll with it.  if things are repeated..so be it...it was interesting enough for someone to talk about again at any given time.  someone else that has or hasnt talked about it may join in.