there's a 50nm sea crossing
You could cross over Skye-Benbecula, reducing the sea distance, then fly south to Barra.
I wonder just how effective a hose down is after, I'd imagine that spray would get up inside the belly and rot the hell out of the plane over time
I've only flown there in a wood/fabric - deliberately. I agree with this quote, especially for a retractable. I've only the wheels to hose down - and then taxi/fly to dry off, otherwise the water lies in the brakes.
PS Solas (beach) is 14-18 June. Going there tomorrow.