Hi,
Several years ago I made a similar boat to what you intend to do.
At the time I had obtained from the library a book entitled, if I recall correctly, 'Edwardian Steam Yachts From Old Glass Slides'. It did not have drawings but provided a good background from which to take ideas from. I used images of a yacht named Zaida from the book and the drawings of Greta referred to above. The F/G hull, made by a friend was based on the Miranda river launch hull.
This was my boat based on those two designs
A model of Greta featured on the cover of Model Boats Mag in 1972
Sorry about the poor quality of the pics but they are all I have on file. The boat sailed regularly before being cased and now sits in the bedroom!
Hopefully they will provide some ideas for you to
Regards - Ramon