@diverjer - fortunately, determining how much you’re peeing into a pad/pull-up is pretty easy.

Weigh a new one (in grams) of whatever you’re using. I cook a lot, so I have a few digital scales, and I just repurposed one of those for the bathroom.

A new pad might weigh about 25g. Now, the next time you change out a pad, weigh the new one. If it’s pretty full, it might weigh 250g. Then just subtract the empty weight from the full weight, in this case 250-25=225, and that’s your amount, because for this purpose, 1 gram is equal to 1 ml.

Just keep track of that during the day and you’ll know.

One other thing…those first two months, where I was going only in my pants, I was naturally sitting down on the toilet, just to do the pad changes.

Once I was able to pee standing up, I was understandably pretty thrilled. I mentioned it to my PT, though, and she said that yes, that was great, but to minimize leaking later, I should stick with sitting down to pee, if my manly ego could stand it ( 😉 ). Apparently, sitting down while peeing allows the bladder to descend a little and lets it more fully empty. Something like that, anyway.