I'm not tinner,but I'll try to help.I have a flager and I
run 26 thru it most of the time,I have the bolts set where the metal run thru with out me having to force it thru when it get to the end.
I have it set at just where a penny will lay flat and flush with the seam.Tt seem to accept 24 guage with no problem but thats the capacity on this machine.
For a tighter pittsburg seam you tighten down on the blots,
for a wider seam you go up on them.
If the metal will not go thru the machine when it get to the end without being force thru you have them to tight and
you are getting close tolerence of the machine and possible
loosing some teeth on the gears.