Just a quick point that no-one has made yet. Surely ATCOs cannot be expected to know the glide performance of different S/E aircraft. For example, one of the aircraft I fly is really a motorglider, but on paper in this country its a group A aircraft. However, it will glide several times as far as a Cessna, even without thermals. I wouldn't expect any ATCO to know this.
By the way, I am one of those people who is very happy to fly at night or in IMC in a single. I do however do lots of sums before flying over water.