- Goal: Minimum logged miles v rhumb line distance

I have to disagree with your "goal". The goal is to complete the passsage! Along the way you will either
a) have had to switch on your electronic gizmos and computers for safety (and now realise beyond doubt how dependent upon them you have become)
b) not have needed them (which gives you a perfect defence against the next slick electronics salesman trying to sell you "essential" kit)

I'll add one proviso. Each yacht shall carry a traditional (non-digital) radio tuned deliberately between stations so that it produces nothing but endless interference and static. Each skippers shall proudly refer to this as "The RDF"!

This sounds like fun. Is BIGNICK doing entertainments? Is Twister Ken doing awards? Whose yacht shall we try to capsize?