This is the current setup i use for soldering.
I have three helping hands with 5 joints each and alligator clips at the end. The original model used screws to keep them in place, i used a lighter to warm the clips and insert them in the joint, melting the plastic. I think it's more rigid this way.
 

The microscope holder is made for one of those cheap generic usb one you can find on amazon or ebay. Use M3 screws and nuts in the appropriate holes to hold the pieces togheter.

The solder spool can carry 100g of solder. I printed the holder with no supports just fine so i didn't bother putting them in the print profile.

Hope you like it and please feel free to add more to this project!