I had a LC Smith with Twist barrels for a while and I loaded paper hulls with pyrodex to a front loader spec I found in an ould Guns and Ammo annual.
I used Win 209 Primers and bought all the fiber wads, over the powder cards, and over the shot cards for the front loaders.
Loaded up 5 or 6 boxes and headed out for the trap range. Tried the shell out in another shotgun first, and then shot for score with the LC Smith. Worked well. The other people on the line were suprised at the huge cloud of smoke that smelled like BBQ.
The animal fat in the wads and the charcoal in the smoke started to smell like a smoker.
Happy the gun worked, I then made some hunting loads of 6's, 7', and 7.5 and used them on a dove, quail, and phesant hunt.
Your other option is to send the gun to someone like Brielly (the choke people) and have them sleeve the barrels with steel and you will be able to use light loads. I would be worried about the hinge pin and the face of the reciever with heavy smokeless loads.
Is it a 10, 12, 16, or 20Ga?
I do not want to give you the 12 ga loading if you have a 16 ga.
I did see someone at a trap range shoot a single shot that had a painted twist barrel and after about the 10th shot on the trap field the barrel unwound.