Bartow Florida 255 And 712 - Difference?

Can anyone explain or show me the difference between the Bartow FL 255 and 712?

In the PSS catalog, the lines (neither has bars) look the same width and are [edit: essentially the same] the same distance apart, they both use 2.5 mm block letters, the 712 supposedly has "narrow" letters and the distance between town and state is 1.6 v. 1.8 mm (ie. too small for me to identify by measuring).

I think I only have one or the other type -- on 1926 issues, Prexies, thru Liberties.

But which?

I've tried measuring the length of the word Bartow, which is 1.3 mm on all my examples -- I was hoping that "narrow" letters would add up to a shorter measurement.

Any ideas? Was one of them used earlier and the other later? Or am I missing something?

Edit: Adding Picture and: The only difference I can see is that on my three 1926 1c p10.5 stamps, the precancel is hugely neater than on all the others from 1922 to Liberty. The left example below is a p11 from 1922. Judging from the pics in the catalog, that might make the 1c a 712 and all my others would be 255. But while it is neater, I don't see it as narrower letters:

Take a damaged copy of the smaller variety, and very precisely cut along the outer edge of both horizontal bars; now you have a template to hold alongside any new Bartow to determine if it's wide or narrow, so to speak, no measuring needed. You could also cut a damaged copy on either side of the word "Bartow" to make a second template. Or you could do it with photocopies.

Bartow is a town FULL of winter-occupied mobile (second) homes, I've been there. Fighting the urge to call them house trailers, LOL.

These two types are VERY close in appearance. So close, that narrative descriptions really fail to help distinguish. The PSS255 will have a cleaner look, the PSS712 fuzzier printing. 80 years after the fact thats about the best we can do. The reason they are considered different is the 255 was a big 100 subject metal plate that required a fancy press to operate. The 712 was a metal 5x5 25 subject that could be applied by hand - usually 4 times per sheet. Different devices = different PSS numbers [usually].