Securely caged

Here are some pictures of my tiny penis secured in a Holy Trainer Nub with a tetherspout and padlock. I found that with just the Nub, I could fairly easily pullout. Not with the tetherspout securely in place! Now to try and combine the tetherspout with an inversion cage. Can't get used to the urethral extensions typically used to prevent pullout.

How long have you been able to wear this with the tether spout in place? What sizes did you end up using? I've tried to use this, but the sizes I got must have been too small as it fell out, and I'm not sure how it would have went if I had left it in long term once I got a size that fit. They are bit expensive to just guess with, but I'd like to get a bigger size in the future.