"Although the 238 gr 45 AR bullet was designed by Keith, it does not encompass the same design characteristics as the 250 gr revolver bullet. If it did, it would weigh 250 gr, and be considerably longer".
Anachronism: I'm a bit lost on this one. Keith designed this slug for the 45 AR, but also for use in the 45 Colt and the 45 Shofield. I believe he cut the weight back a bit for the later two shorter cases but it is a Keith design: two grease grooves, wider front leading band, large metplat. The 250 gn 454190 is not a Keith design (although I am sure there are 250 gn swc slugs out there that mimic it) and the only real difference twixt the 255 gn 454424 and the 454423 is the slightly longer nose on the later. In fact, if you cast the 454423 soft enough for the slower velocities of the acp or the ar you usually drop a slug that weighs anywhere from 248 gns to 250 gns.
reliquary: I like the look and feel of the 1917 Smith and Wesson revolvers and prefer them in one piece, including the hand that holds them. I would start with modest loads, as you stated, but not bother working up too far in a 80 y/o revolver. Regardless of the bullet weight you use, the one major factor improving the on target performance of any (45 caliber) revolver round that has evolved from the black powder days is the square shouldered flat metplat design of Keith and Thompson orgin. These bullets do not have to be moving any faster than the original loads to perform better, as the impact effect of the flat metplat is much more effective than the old round nose design.
The round nose design was a hold over from the old mini-ball concept for use with black powder (iirc). It also made reloading the cylinder on those old wheelguns a tad easier under stress than flat nosed slugs but it was Keith and Thompson who thought up the flat nose design for more effective use in handgun hunting (I believe) but not too much later the use of that design in police work began to show up long before any factory used the design.