last September i have visit this big PN. I use my Filter Switcher (OIII/H-beta) on my 21". The changes was impressive for me so i take two sketches (see below). The transparency was very good on the Wasserkuppe (mountain in Germany). With OIII Filter the PN the visible was good with a dark separation in the PN. With a H-Beta Filter the shape was change (U-Shape). Two faint segments was visible with indirect Vision. Without a Filter the PN was invisible.
Sketch, 21" (Wasserkuppe,Rhön)
Maybe you try too see this PN. I think 16" (maybe 14") is enough for OIII and very good condition.
I want to contribute the very informative OOTW, written by Reiner Vogel in 2013.
The Hß observation and sketch is still in my waiting queue. Perhaps it could be an idea to bring both sketches together in one sketch? Almost a bi-color result.