Head Machining question

[RD7]

Machining Combustion Bowls

Hi I have been working at setting the squish and compression ratio of a couple Air Cooled RD 350 top ends. They are to be used on a 4 cylinder 700cc RD based sidecar.
I have been using the information from this forum and Chuck's photo's for guidance.

The cylinders have been O ringed, the heads have been centralised to the bore and dowelled, and squish has been set at 0.9mm. The angle of the squish band is 14 degrees.

Presently I am preparing to machine the bowls and have some questions.

From my workings to get a 43% squish band the inner diameter of   band should be 48mm (radius 24). However from Chuck's photos the radius cutter is set to a lot more than this.
What radius should the cutter be set to?

Regarding Compression ratios

It is intended to run on 98 octane or better premix. With Electrex world CDI ignition with advance and retard curve.

Initially   thinking to set the compression ratio of cylinders 1 and 4 to 6.7:1 and cylinders 2 & 3 to 6.5:1.
The lower ratio of the inner cylinders is an attempt to mitigate the lesser cooling.

The exhaust port is presently 28mm down from the top.

Once running and reliable it is planned to raise the EX port to 27mm. This will lower the CR of cylinders 1 & 4 to 6.5:1 and 2 & 3 to 6.3:1.

Do these numbers look right?
Thanks for reading all this.