As far as flushing, I've never had to flush since the catheter was removed. I used saline for irrigation which is much easier to get than water. Maybe it's less expensive. Mine was covered by insurance. My incontinence supplies; however are not covered and are running about $150 a month.
As far as potency, I haven't had an erection since 10/09 after the urethroplasty, so I told my urologist no need to worry about nerve sparing for the neobladder since nothing works anyway.
As regards incontinence devices, I think I've tried every variety known to man. I'm not sure how the Cunningham clamp differs from the j-clamp. I use the j-clamp when I get out of the shower and when I transition between devices. After 1.5 hours I start to have intense penile pain, and I leak even with the clamp set on the highest setting after I've been wearing it for a while. I had to use it for my last CT scan so that I would retain dye in the bladder.
During the day I use the AFEX system which is essentially a semi rigid funnel in the underpants that attaches to a bag. As with all the devices, I have to change positions slowly to avoid yanking my penis out of the device.
During the night I use the GeeWhiz, a condom catheter that attaches to the penis with a silicon strip and tape over the condom. Although I think I've mastered applying it so that it's unlikely to detach, reapplying it is not so easy that I would chance using it at work. I have an overnight bag and long tubing. The AFEX wouldn't be good for night sine it doesn't seal with the body, although I find mine does form a suction. In any event, I find all the devices become irritating after a while, so that switching from one to another gives the sore spots a break, since each device irritates in a different manner.
I've also switched off to the McGuire type device, but it holds too little to be practical and the outlet is a screw cap which guarantees it will get lost and you'll get pee on your hands. It comes with a leg bag, but the tubing is too short to put it down on the calf. I'm working on getting different tubing to which I'll try to attach the connector.
-Warren