I have a Toto Aquia toilet with a COCO bidet seat in my very narrow prewar NYC bathroom. My fiance will be having hip replacement surgery soon, and we need to do something about raising the toilet seat. I'd rather not take off the bidet seat entirely for his recovery period, but I do need to raise it up so that the toilet is high enough.

Does it work to put a toilet seat riser underneath the bidet seat? (And how do you get long enough bolts to hold it all together?)

I found this, which claims to work with most models but hasn't been tested with the COCO:

http://www.bidetsplus.com/toilet-seat-riser.html

And then I saw this, which looks the same but much cheaper:

http://www.atgstores.com/toilet-accessibility/essential-medical-b5081-elongated-toilet-riser_9909390.html

Has anyone out there tried this concept? Should I just buy something, call my plumber, and hope? (I'm worried that it won't be returnable.)

(Unfortunately we can't use one of those one of those freestanding frames with the toilet seat on it, because we have zero space on either side of the toilet. It's prewar.)