To address the 2" gauge fitment question, here's my 2" (52mm) VDO gauge installed. You can hardly notice it's a smaller diameter than the 2 1/8" OEM. Not a perfect match, but it will do until I replace all of them. I p-shop'd the silver ring on the fuel gauge. I'll probably paint all of them to get rind of the silver ring anyway.
As seen here, I didn't use the long spacers that normally go in between the plastic retainer and the back of the gauge. Reason being the new gauge isn't as
deep as the OEM so it wouldn't snug up. I also had to use a machined
thread to compression thread brass adapter for the VDO gauge. The new
gauge uses the same OEM light bulb, it's a little brighter, but again I
can live with it for now.