reverend, the caps from my custom have 223 on them, the ones from my Standards have 333 and are slightly larger. I don't have a meter that can measure capacitance, but those two different caps are almost identical to the Radio Shack "green chiclets" that are .022 and .033 respectively. So my guess is .022.
I like to experiment with different spec caps anyway, so a while back I bought several 5% tolerance Mallory 150s in each of these sizes from Mouser: .022, .033, .047 and .1.
Here's a link to the .022, which is the size I use most often including this Custom with P-90s; and
here's a link to guitarpartsresource's page that lists those 150s in several popular sizes. I think Mouser is cheaper
if you're buying a good handful (shipping is more expensive than guitarpartsresource), but they are easier to find on guitarpartsresource. At the time I bought my stash guitarpartsresource didn't have them.
On my Squier Tele Custom, just like my Squier Standard Teles, the stock volume pots were dime-size split shaft linear taper 500k; the tone pots were the same except for being audio taper. I decided to try some Alpha pots for this P-90 project, so I ordered some from Antique Electronics
here. I stuck with the same electronic spec as the stock (500k, linear volume, audio tone) but they are the 3/8" bushing with a 1/4" diameter solid shaft. I had to enlarge the holes in the stock Squier pickguard slightly (small round file), but they fit the Fender '72 Deluxe/Custom knobs I'm using perfectly.