Changing the rocker cover gaskets in a week or two or sometime ….. anything else that Forum members would recommend doing when I start the project whilst I’m at it?
Got to get the bloody dash fan thing sorted first though…..

gems or thor? I suppose while you're there you have better access to leads/ plugs and the breathers on the casing. I would also give the rocker covers a nice coat of black hammerite smooth - i did mine a couple of years ago and looks v good still. Not sure the most effective way to clean the inside of the covers - there should be a better way than i did it (rags and solvent). BTW, you know that ideally you need a 12 point socket for the rocker cover ? ideally...8mm & long/ narrow

Yes, the socket, ideally 1/4" drive, is essential. First time I wanted to take the rocker covers off, went into my local toolstation and told the guy I needed a 12 point, 8mm socket. He went away and came back with a 13mm one saying it should be close enough......

….. any opinions on the brand of gaskets themselves?

Not sure it matters so much...mine were britpart...it's just HGs where there is no compromise

To get the rocker covers out, how do you deal with the Thor "bunch of bananas" intake? Is it in the way?
Someday I gotta do this job as well. ....

Take them off, the same goes for the intake on the GEMS and, in both cases, the coolant hoses to the heater matrix on the other side. In JMCL's case, he'll probably have to deal with the SAI system on a US spec car too.

Just thought I'd mention super glue cover gasket to cover on reassembly as it helps immensely