Skimmer design - neck diameter / length

[AndyL]

Yeah Peter R's book is only occasionally appearing on ebay (and on cd from some australian company for 220$), selling for big $ - doubt I'll ever get my hands on a copy

I know some of the skimmer nuts on RC toss around numbers - but they just magically appear from thin air... I'm pretty sure I need a 1 1/2" neck, and likely I'm going to want it about 8-10" long (of course that can be adjusted by adjusting water level). However Its nice to have the design work on paper before being built