Hi Tracy
I've been away from the forum for a long time, and I think it is karma that yours is the first post I see upon my return. I've been braiding leashes now for close to 10 years, and the last time I took the time to count (2009), I was up over 500 individual leashes and collars, with more than 21,000 braided inches. I'm probably double or even triple that now.
As for beveling making a difference, the majority of those who say it doesn't make a difference are usually those who can't, won't or don't know how.
Nobody that I know sells pre-beveled lace in an any quantity - maybe a yard or two at most. Degree of bevel is a personal thing, as is the amount taken off. I personally like no edge at all, when I can do it, as I find that the less edge, the smoother the braid is after rolling, and the tighter it is as well.
Beveling (when done right) does not affect the width of the lace, only the thickness at the edge. Your leashes might be thinner than those of someone who does not bevel, but if your braiding is tight and consistent, you will have a much more attractive product.
If you are braiding for yourself, there is nothing more satisfying than making a beautiful product. If you are thinking of braiding for sales, be advised that MOST braiders (there are some exceptions) who make show leashes are notoriously unhelpful to newbies, and the market is flooded with all kinds of leashes that range from amazingly beautiful pieces of artwork to absolute crap that is not suitable to take a dog out at midnight when nobody will see you.
Good luck!
Beth
Lucky Kanga leashes