.015 if you want a smidge less bass, but want to retain that smooth, rolled-off sound. Any lower and you start to get some actual twang even with the tone all the way down.
Those values are ok. You may like that value with some pups, maybe not as much with others, particularly with neck pups. I like .015 in the neck with certain pups. It's a matter of degrees...personal preference.
Something to bear in mind is that more often than not, old caps will have drifted from their original value. I have removed many bumblebees, black cats and so on from old radios, etc. I have a bunch of 'em. All of them have drifted so far that they are of no use in a guitar. I wouldn't buy into any hype (not suggesting you are) that the old caps have some special magic that will make your guitar sound better. A set of new Orange Drops will do just fine, and they're cheap. Hovlands are very nice as well, but more $$. If you have (or can find) a multimeter that measures capacitance, you can check the old ones before you decide to try them. Whatever caps you use should be rated at a minimum of 400 VDC. 600 VDC is fine, but the larger the VDC rating, the larger the cap size.