Do bicycle tube patches work to repair he 495s? I wouldn't worry much about the $3-4 dollar models, but It seems like it would be worth patching a $16 glove.
Aquaseal will work fine to patch pinhole or slice damage, but that rarely happens, in my experience. The Aquaseal repair will be flexible and last forever, especially if a couple of thinner coats are used.
I've found it's very hard to
tear the Atlas 495 or 660 pvc glove, and I've manhandled some rusty, barnacle-covered anchors and chains with these gloves. I wouldn't worry unless you expect to work them
real hard! You could put some garden gloves over them, if needed.
I have several sizes of both the 495's and 660's for wearing over different liners in different water temps. In general, as fdog said, you'll need 2 sizes larger in the 660's than in the 495's, and, even then, the 660's skinnier fingers may be a little tight when gripping something.
I've found the 495's looser fit is warmer and the dexterity is fine when the air moves out of the glove in the typical lower position. Working overhead will fill the glove with air and may make the loose fit too sloppy for fine dexterity.... I'll sometimes need to lower my gloves to compress them and then quickly reach up to do the task, such as untying a knot, etc.
A loose fit is definitely warmer in either model. If you squeeze a second liner into too small a glove, it may end up actually making your hands much colder. I've done it....
Dave C