Thanks folks for all the input!
My thoughts on this were that if RD is usable for 1 1/4oz loads in short roll crimped Remmington cases with a SP10 and anything but a CCI209M or FED209A it would also...
Probably still be hot enough to work in longer cases with some cards under or in the SP10 at the same powder charge.
Might still be hot enough to work in the longer(and of course shorter) cases with fiber wads.
Might still yet again be hot enough to work with an ounce and an eighth.
Be bulky enough not to migrate, seems to be some wiggle in the hull, especially the Federals....Longshot is one of my favorites, but it flows like the sands of time.....
Be bulky enough to not need as many spacers or fillers.
Be somewhat frugal at 20 to 25 grains a pop.
I have no intention of trying to get lots of velocity or really low pressures....1100 to 1200fps and 9k'ish psi should be just fine for targets in a post war/NID strength gun.
As I alluded to above, I roll crimp all my 10ga loads, which makes for easy crimp depth adjustments to bump pressures up or down and account for different shot column hights.
Jerry, thanks for the offer on the data, but I THINK I have it already, courtesy of RWG a couple of years ago (you were the author though

).
Bill S, that is golden info, would assume that is fiber wad data from that time period....did they at least mention the length of the shell?
JDW, good stuff as well....should help with a little "extrapolation" to RD values. Going forward though, be very careful with the skipping of the fillers and using the same data for shorter hulls, in any gauge. Pretty sure thats going to spike pressures. Most shotgun powders can be very sensitive to finished hull length/volume. Not sure if you caught this from my above comments but in the other direction, if you have data for a short hull and try to load it in a longer case with fillers.....you are usually looking at decreased velocity and pressure. Which is sometimes just what you might be looking for, but might also, in the extreme, drop the load so low in pressure it might be prone to "Bloopers"....which might even leave the wad in the barrel after the shot?
Makes for not so good situation when next round gets fired if you don't notice it.
My best to all,
Mark