Metal shrouds can get pretty warm. I worked on a Speedster the other day and after running about 20 minutes(it was 87 degrees out) you couldn't keep your hand on the throttle linkage(hexbar style), it was too warm to hold it. The engine had no tins yet, and it also didn't have the doghouse oil cooler tin, so the engine compartment got pretty hot.
The fuel lines on this Speedster are run on the firewall separately to each carb, this worked well, no vapor lock.
Once on my Spyder I tried running the fuel line from one carb to the other, but by the transmission. Only time I ever got vapor lock.
I switched back to my original setup, metal line down the center tunnel. Teed at the bottom of the firewall, metal lines outward then up in front of each carb. Then a short rubber hose to each carb. This has been flawless for me over 15 years.
I recommend the same on a Speedster, running low and separate lines to each carb if you can.
On Webers, you can buy the plugs and/or the fuel inlet fittings. On Dells if you can't purchase a single fuel fitting, you can cap and clamp one bib on the double.