Nice work!
The low pipe is period correct for a 60s flat tracker, if it was good enough for Cal Rayborn and Malcolm Smith, it's good enough for us. I'm even keeping the CB low pipes on my 250 CL, just adding bigger mufflers like the Ducati you posted. Your header/muffler combo just screams Matchless G50 (in half scale).
One thing that has always stood out and screamed "We cheaped out" on Japanese bikes is the gas tank seam. I either hide them or emphasize them with door edge aka bug shield trim. Black hides them, chrome or gold makes them stand out like an intentional design element. If you do yours in black it would tie in nicely with the tank and fender stripes. Enough to do that tank would probably set you back about 5-10 pounds...
I have a feeling that 1/4 liter bikes are the next craze... gas here went up 21 cents per gallon in 4 days. When you draw less than $300 USD per week, and get paid irregularly, 80-90 some odd miles per gallon looks a whole lot better.
Especially when it looks like your bike.