Whatsup ents. I got myself a Mobius Strato w/ Matrix perc about a month ago (thread here). I have an SGW inline ashcatcher, but I want something much smaller, possibly inline. Basically, the smallest possible ashcatcher that will reliably catch ash and keep my bong clean.
A dd slide does the job surprisingly well man, headford has some decent inline a/cs that are quite small
If keeping ash out of your tube is your main concern I would look at a carbon filter. They are pretty small and do a great job of keeping your tube clean.
I second this. I have just a 12" tube with an A/C and the water in my tube is always crystal clear. No ash or anything.