HI Intairco.
Good to see your post and appreciate you have been 'at it' for some years, I like your products and think they are well designed and I have respect for your experience and resulting market view.
I do have a 'personal' preference about the fittings used on my products (I did design them after all) but do appreciate customers also have their own preferences.
The original CAT and CAT V2 have barbs, the new D-CAT has chrome barbs supplied as standard but as the threaded holes are now M7 this allows the customer to use push fit connectors if he chooses.
Just for the record however, and for 'factual' reference the barbs supplied with the new D-CAT 140 and 240 are 4.7mm ID, the Tygon tube I use for sizing is from
Saint Gobain and is 8mm OD with an ID almost bang on 4.7mm. A 4mm ID bore is 12.56mm2, a 4.7mm bore is 17.34mm2 - around 38% larger.
marcs