The P-07 comes with +2 base plates installed on the 2 magazines.
With the +2 extensions the grip length of the P-07 is just slightly smaller than a P-09 with regular magazine plates, like not even a 1/4" I believe.
You also get 2 more rounds in the P-09 this way for a total of 19 in the magazine.
It seems that a lot of people that are concealing the P-07 are doing so with the +2 plates installed.
Slide length isn't a concern for me concealing, grip length is much more of a concern as far as printing and comfort for me.
I have 2 UG P-09's, 1 FDE P-09, 1 UG P-07, 1 FDE P-07.
Every day its either the UG P-07 or P-09, I carry IWB with a stealthgear holster.
Their holster for the P-09 just fits the threaded barrel of the P-07, although I used a heat gun for 25 seconds and pushed in the threaded P-09 so the holster flared at the end for the barrel.
Looks as though it was made that way.
So with that holster I've been carry both models.
I find myself carrying the P-09 more.
I set a magazine up with the regular plate for carry.
I'm 5'8" 146 lbs. T shirt and jeans.
If I had to pick one it would be the P-09.
ETA if regular plates are used, hands down the P-07 is easier to conceal.