my "point" is that the OP has been altering things and adding info this entire thread, most of the info is now posted, and several of us are trying to help him...
what i don't want is to get into a pointless waste of time with your pointless questions and comments.

I believe i have my answer. I thank everyone for their advice.

so, it seems the total added teeth in the planned swapping is 4 teeth... that would indicate, if the derailleurs don't get swapped, or if they are the same basic tension arm and roller design/size... add at least 2 links, but start out at an extra 4 links, then shorten if needed.

thanks for the additional and/or corrected info. .

The RD is getting swapped. From Sora to 4700. That was in the OP.

52 x 12-25! Where do you live? Downhill?

Pointless comments - you mean like several posts assuming OP meant something other than what was clearly said, or going on about freehub compatibility?

lol....dude, I know. But, i just want to try it. My roads are so freaking flat and we'll paved!

Looking at classic derailleurs but ignoring pre-parallelogram designs, the Suntour Superbe is the only one I could find with 23t max, Suntour Cyclone and V Luxe were 24t along with a few like Simplex Prestige, Huret Jubilee etc. Then skip to 26t for Campy Gran Sport, 980 and various Record, NR, SR models, Suntour Vx and Cyclone II, and Dura-Ace. Finally 28t for Shimano 600 and "bird" models.

I thought there was a old Shimano RD I looked up for someone in another thread that was 23 teeth for the max low sprocket. Maybe not.

Still, the advise remains.... One should check the spec's of their RD to know whether they are within spec. Or are about to be experimental. Not that going out of spec means immediate failure. Given a choice of RD's, new or used I'd get the one that's in spec.

Digging a bit deeper, the 1960s "3.3.3" derailleur came in 24t and 28t, the difference seems to have been the length of the hanger. But I'm not seeing any 23t - maybe Shimano specified 23t but Sutherland's knew better?
Indeed - know if it should just work, or if you're pushing the limits. Various factors like the length of the hanger and the width of the freewheel will influence your results.

Just buy a new 10-speed chain.