estimating SM weights.

I just got back from fishing the neshaminy creek below Tyler Park in Bucks
Co. Pa. ( not know for big bass)

Just taking a break from LM fishing in the local lake and thought I'd go
cool off in the creek & get some small bass and panfish. It's been awful hot
here.

I caught a 19" SM on a Rebel crayfish with crushed barbs. Used 6 lb trilene
& didn't think I'd get the fish in hand.
He jumped three times and I managed to keep the line taught. I knew I'd lose
him if I gave him line since I crush my barbs when I use treble hooks. I'm
C&R but I had to admit I had thoughts of keeping this beauty.

I measured it against my rod and when I got home measured the mark on the
rod and found the fish was exactly 19".
I don't know the girth so I can't use the formula (LxG/1200)

Can anyone give me an idea of what the average 19" SM weighs

Sure would appreciate some input. Wow, I'm still excited

Jim L