The person who you probably ought to talk to is 2Donkeys (although he went IFR), but I'm not sure if he frequents PPrune anymore. You may be able to contact him via
The flyer forums.
He's been to Vagar, and considered routing via there when he flew accross the Atlantic last year in his TB20. In the end he decided not to as the weather there tends to be bad and very changable. These extracts from his blog illustrate the point
The scary bit about Vagar is the weather. Vagar has one of the worst fog records for the whole of Europe. Visibility is frequently down below approach minima, and in a further twist, the low visibility is often combined with terrific wind shear during the last 1000 feet of the approach, sufficiently so, that an 850 foot wind report is always included in the METAR.
and
TAFs from Vagar almost invariably offer PROB40 TEMPO (unlandable)
This is for an IFR arrival, VFR is going to be even harder.
One more point, I believe that most (or perhaps all) of the North Atlantic is covered by class A controlled airspace starting at FL50, so you may not be able to do the crossing at FL75.
I don't think that its impossible to do, but I doubt it would be very easy. I think you'd need to plan on having enough fuel to go there
and back without landing, just in case.
Sorry to be so pessimistic
Brooklands