There's zero chance that good results will be obtained with the 9-18mm behind the 3.5" or 4.33" dome ports. These ports are far too curved to allow the corners to have any chance of ever being in focus.
The 9-18mm behind the 4" semi-dome (which has the same optical radius as the 6" semi-dome for the 7-14mm) with a +2 diopter looks excellent.
12mm test results behind the 4.33" dome:
Storker's 9-18mm test results behind the 4" semi-dome:
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