I just use a Milbro mate, soft square elastic, or single 4070 tube, mostly the tube these days, i don't think it matters what you use if you get on with it, and it does the job.
Ok mate.....I've been messing about with a catty for a year or so now & I got a terrier knocking about here as well, so who knows...maybe I'll give it a go one day :-). You sound like an 'old hand' at that game, so I'm interested in any trade secrets....;-)