I have TTI base pads on all 3 of my Carry Optics pistols. M&P CORE, Glock 34 MOS, and now Sig P320. The Sig mags are much much much harder to get 23 rounds in the magazine. The M&P is by far the easiest, with 23 rounds in the magazine, you can still compress the rounds another ~2mm, super easy to load. The Glock is still way easier than the Sig, once there are 23 rounds in the magazine, you can just barely compress the rounds by maybe 1mm. With the Sig magazines, I had to press harder than ever to get the 23rd round in. I can get it to load in the P320 on a closed slide, surprisingly with ease, but I have not had a chance to see how well the gun functions with these mags loaded to 23 rounds. Forgot to add these are 21 round magazine tubes with +1 TTI basepads.
Currently, I have 3 P320 mags loaded to 23 rounds just sitting in the safe, I hope this will help.