just my opinion, but wire wheels with lugnuts just don't look right in the XJ-6 body or in any car for that matter, they look "faky", not to mention that any wire wheels are a PITA to keep sparkling! Plan on spending an entire day per wheel just to detail them. I know about that, my '65 S type has chromed wires with spinners, and it's an EXhausting job to clean them.
Also, there are other styles of Jaguar wheels for the period of your Jaguar, other than the ugly "Kent" style wheels that they came with originally. And as you know already, wires become loose and they also leak. Just read some of the threads about wires here.
Again, just my opinion, it's your party and you can cry if you want to!
Ex