All true Chris, however Messrs. JAO and JSO Oliver made a series of in-line twins, and they run. Have you a copy of the book 'Two Olivers and a Tiger" by John Goddall? Lots of shots of the Oliver twins (mostly based on Majors) with R/C carbs powering large Vintage ships.

At full blatt the CS twin runs fine. The only indication of mixture disparity is that the front cylinder exhaust is slightly darkened, to a honey colour, while the rear is light amber. No doubt due to the leaner fuel/air mix.

Jon is working on another CS .30 twin and after some sleuthing advises there is disparity in the shaft bore diameters:

"checked the bores at either end of the central shaft which to my surprise, are different dias. Front hole is 0.205” dia. and rear is 0.213” dia."

Sleeving down the rear shaft bore to 'even' the diameters appears to be the best way to proceed.