I wanna be a record/music producer

I've produced a few people's songs in the past, including creating complete songs (drums, bass, guitars, keys, etc) from just a guitar or piano part and vocals.  The few clients I've had were very satisfied with the results, and since that time I've improved my mixing and mastering skills.  I also have around 80 finished songs that I've written and recorded myself.  I don't have a great singing voice, but otherwise I think the songs sound pretty good.

My son is moving out next month and I'm on disability because of my back (spinal stenosis), so I will have an empty house and a lot of free time.  I've been seriously thinking of taking the next step and start advertising locally (this is a college town with a lot of musicians) and start taking on clients on a regular basis.
I'd limit the work to solo singer-songwriters, or perhaps duos.  I don't have much more room for anything bigger in my home studio.  I'd also limit my customers to the styles of music I know (in other words, no hip-hop or rap)

I have pretty much everything I need to produce demo tapes or even fully mastered CDs.  I'd need to buy a couple of things, like another mic and stand, in case they want to record guitar and vocals at the same time (as a scratch take).   My home studio looks totally professional, it's got sound treatment on all the walls, cool colored lights and equipment and supplies to create professional looking CD's.  And of course I have Sonar Platinum with hundreds of plugins and virtual instruments of every kind, and Ozone 7 for mastering.
I have a full size 88 keys midi keyboard, with weighted and touch sensitive keys.  I have two in-house guitars, one is a Fender Strat and the other is a low priced acoustic. 

So, of course, the obvious question is what to charge?   I'm on disability insurance and own my home (no mortgage) so I really don't need the money and don't have to charge a whole lot, but I don't want to undercharge either because that gives off a negative impression, that I don't know what I'm doing.    I was thinking of charging by the song.  Maybe somewhere between $50 and $100 per song, discounts for multiple songs.  And guarantee the work: If they're not satisfied, they don't have to pay until they are. 

Alrighty then, I guess you get the picture.   I'm looking for advice and tips from you folks that have produced music for a living, or at least as a hobby but know what you're doing.   Any suggestions on pricing, legal issues, copyright stuff, or co-writing issues and royalties (if by any chance a song I (co-write or) produce starts making money).  And/or if you could point me to a website for wanna-be music producers, that would be helpful too.
Sorry for the long post, but I wanted to give as much information as possible in return for some reliable advice.  Thanks for reading!

I am not a pro.  Hobbyist only, but have thought about the same things.
Here are some links I looked at:
https://theproaudiofiles.com/charging-hourly-rate-vs-per-song/
 
http://www.homestudiocorner.com/charging-for-your-work/
 
The very LAST entry on this forum:
https://recording.org/threads/studios-that-charge-by-the-song.23352/
 
And at one point Graham at the Recording Revolution had a video on this that was free.  It had a lot of good info in it.  It may still be on youtube.
 
 
 

I hope you'll do a follow-up to this and let us know how it goes.