Howdy Budgie....right you are.....thats not being a spoiler but
just being helpful . Must admit I based my experience has been with
the positive VR's (obvious eh!). Having said that......the tab of a
79xx wouldn't necessarily need to be insulated but it has to be kept in
mind for sure. (anyone here ever tried building their regulator into a
grounded side of a rectifier heheh......it works just fine - just looks
disconcerting when you look at the diagram).