HDV record to any MiniDV tape. The companies market HD tapes because they are "better" and can therefore charge more.
Since your HVX doesn't record using the HDV codec, there is no point for you to get these tapes. You can record SD only through the MiniDV deck on the HVX.
I 2nd the Panny advanced master tapes. Amazing tapes and they do not get drop outs. I know as I have many several years old that have been pretty abused and I haven't gotten any dropouts.
The biggest thing though is stay away from sony tapes on panny cameras. Bad news.