Plasterboard Fixings

The metal 'RediDrivas' (big spiral thread jobbies) are quite good - but not really suitable for heavy loads.

Screwfix do a 'Heavy Duty' version

My own preference is to cut a 1" hole in the plasterboard, and to use a long screw going into the brick/blockwork, with a suitable spacer made out of 1" dowelling (or broomstick). You can then get a solid fixing without squeezing the plasterboard towards the blocks.

I think your description of the first fixing is these ?

The second description seems to be these

The strongest plasterboard fixings IME are these

Hollow wall anchors - providing the fittings have large enough holes for the 5mm screw.

I always fix a batten on the wall, and then screw the brackets onto that. That spreads the load and is far better than individual point fixings into the wall. If you use a pelmet, it doesn't even show.

Yes it does. You can screw them in as you say, the setting tool makes it faster.

I have done that, but I've found customers don't like the idea. Sometimes you have to simply tell them its the only way you are prepared to do the job. Pelmets do seem to be making a comeback!