Ok, update for those playing along. Firstly, I haven't had time to get my WBO2 sensor hooked up. Life has unfortunately been in the way. With that said, I did get a 38/38 Weber put in, so problems are bit different now. I guess at this point this thread is just for me to catalog my changes and to hopefully help someone else in the future. Current setup is 38/38 with 45 idle jets 1 1/2 turns out, 150 MJs and 180 correctors. Car runs well and will get to redline, but only if I'm easy on the gas pedal. If I floor it it will stumble until I ease the accelerator off a bit. Checked screen at pump and cleaned it out, screen in carb is clean and pickup sender is clean as well. I'm at the point now where the issue seems to be either with the fuel delivery in some way (still need to hook up the pressure gauge and see what it's doing when it stumbles) or it's to do with the ignition. My MPG last tankful (or thereabouts) was ~20mpg, which led me to think that I'm still running rich, hence the change to 150 MJs from the prior 155 MJs.