PONNIAH123,
Insurance isn't your problem, it is the technical/regulatory issues around Ferry tanks (can you get it fitted, with it fitted can you accompany the ferry pilot) I don't know the answers (and they depend on what register you have the aircraft on). There is going to be a ferry pilot in the plane (and he will have an IR rating so the original qustion of VFR only isn't really a problem) or else you won't get insurance and you have to have atleast SAR insurance.
You assessment of the risks being more weather and planning than mechanical failure is correct. VFR only, un-tanked, no prior maximum endurance flying (i.e. where you would be without a ferry pilot) is a planning error in the making. That is why having an experienced single engine transatlantic pilot is critical to success (and why the insurer will demand it). Hence, why the key question is the technical one of 'can you fly along with the ferry pilot in the planned aircraft configuration'