Roger Receveau's account of testing the He 274 and Do 335 is reproduced (in French) on Jean Houben's wonderful site
"histoires d'aviateurs.." - if a Frenchman has flown it, there's a report here...
The French even tested (on the ground) the explosive bolt system designed to jettison the Do 335's rear prop for pilot bail out - needless to say, "it proved totally ineffective.."
http://aviateurs.e-monsite.com/pages...bizartres.html
the Lela Presse website is
http://www.avions-bateaux.com/
they have an NC 900 title in preparation