That sounds indeed some how complicated. For me it was maybe a litte bit easier because I was all-ready working a pretty long time in the company when my trouble had started. Short before I was coming back from the hospital I had a talk with our representative for people with disabilities. He help me for instance in that way that we got bins in the stalls. Luckily I have my own office and also no problems with "close monitoring" - at last not in the way that people sitting in my back and looking what I do. It's more that I have to deliver in time and budget. Most of my nearer collegues know meanwhile about my problem and things had become are pretty relaxed.
If I would go for a new job I would be open about my problem in the job interview. I don't think that this is a bigger problem because this "disability" don't hinder me to do my job as anybody else would do it without this problem - and if the company have a problem with it then it's not the right company for me... This give both parties a better understanding and you have the backing from HR if one of the bosses think you spent to much time on the toilet. If it comes to new colleagues I would't be that open. If someone ask me privat I would tell him about it, but it but this is nothing for a round of introduction.
For me it's more or less the same as for you, I go round about 8 times to the toilet over the working day but in this 3 years where I have this problem now no one had asked me why. I think most people don't care about it. There was only that pure guy who had started joking about the new bins in the stalls but after the show he never said word about it again and is very obliging to me ...

More over I'd never tried to were pads or diapers over the whole day. In the first time I had to change the pad every two or three hours. Meanwhile it's mostly just for security. I still have to change sometimes in the morning when I arrive and the drive was to long, or sometimes I forget my timing while I'm in a meeting and have an accident because I mention it late but in this case I change and thats it. So I don't have to worry about leaks or smelling.
I'd learned not to worry that much about all this. In the end it's my live - and I have to cope with this dammed UIC. So I think I have all the right to to make it manageable for me. I do my best to hide my problem, but there are limits that are not made by me. I'm not sure - but in a situation where only half open stalls are available I think I would't care ether. If really a stupid idiot have nothing better to do as to stare over it I would exactly know what I have to do with him.
So my suggestion would be: Relax.
My experiance is: If you are good in what you are doing it matters litte if you have some special needs because in a working context the people will (normaly) respect you mostly for work. If not, then often not the special needs are the problem.