Very good point FunCycle and I do plan to do this.
In trying to figure out what will fit, purely based off of the BCI numbers, I used the jegs BCI chart and made a spreadsheet, so I could sort/filter. Filtering on numbers based on the Group 34 and lower, this is what we get :
Here is the spreadsheet if anyone wants to copy it for their own use.
We really don't have a lot of choices. And based on this, the group 24 and 25 batteries that have been mentioned will not work. The 24 and 25 are 8 7/8 tall, which may work as some have stated, but given that I'll be putting an adapter plate in on my 2019, I'd rather go shorter.
I think the 26 or the 42 are ideal, but finding them in an AGM may be challenging