Judging from your request, this may not be eactly what you require, however it will be a start. Photos of the ER-4 appeared in the old Monogram Close-Up 8, on the Fw 190F on page 11 while detailed drawing views of the ETC 501 were first created by D.H. Coosey for the English Scale Models magazine many years ago. Subsequently, excellent scale drawings of these carriers can be found in Arthur l. Bentley's fine work. See
http://www.albentley-drawings.com/main htm
Hal