Hi
Sorry to hear about your bend and that you have been diagnosed with a PFO. I also was quite relieved to find out I had a PFO after suffering a series of bends because at least I could get it fixed without having to knock diving on the head. I have since had the operation and am back diving deep again without reoccurence of the numerous past DCI symptons.
As for depth limits I was treated for a vestibula bend by DDRC - 7 days of treatement that did not completly clear up the dizziness, I just got bored. (After day 6 my greatest improvement was after a pub-crawl down the barbican, instead of being giddy I could walk straight). One of the doctors there was quite pragmatic and said I didn't need a depth limit after all I had been diving often enough to know when I had increased risk of getting a hit and if I received a bad one I could always return for more treatment.
I did find that diving with air dilutent I was always fine only with Helium did I suffer symptons. My unqualified theory is the relative molecular size being a major effect. I succesfully tested this theory on air dives up to 65m on an unavoidable trip to the Solomons only 2 months after the bad hit.
Good luck with your further testing and if you do decide to go for the closure op then I will be more than happy to share my experience.
There is a good graphic deployment at the amplatzer website:
http://www.amplatzer.com/us/products/asd.html
Gerard.