I would agree with the majority, that you won't hurt anything using the patching that you have been using. Another thing is that thicker patching, at least in theory, holds more lube.
Beyond that, I have a couple of comments. Most of the fellows here seem to get their patch material at a fabric store, and we've had repeated discussions regarding fabric thickness. There's nothing wrong with that. This is a discussion board, after all. However, there are several outfits, such
Eastern Maine Shooting Supplies, Inc. and
RMC/Ox-Yoke who produce excellent fabrics of consistent thickness specifically for shooting. They help support our hobby. I use their products. I have no issues with Jo-Ann's, but I like to support the people who support us.
Not all ticking is created equal. Some has the stripes printed on (I think Crazy Crow's ticking may be printed) and some has the stripes woven in. You can tell which is which by looking at the backside. The type with the woven-in stripes is usually considered of better quality. The dealers who sell patching made of blue-striped ticking usually advertise it as .018" thick, and they usually state that you don't need to wash it before using. I checked what I have, from Eastern Maine Shooting Supplies, and it is spot on at .018". There is a red-striped ticking that is reportedly thinner, but you don't see it much.
October Country does sell both colors, stating the red-striped ticking is .015", while the blue is .018".
Best of luck to you!
Notchy Bob