[old_tv_nut]

Well, the schematic image that was posted is almost too fuzzy to read, but if I am reading it right, the 10 pf is the one on the right and the 5 pf is in series to the left and then goes to the horiz drive adjustment variable cap. I can't make out the range of the variable cap, but I suspect it's great enough to handle a change from 3.33 pf to 3.53 pf, which is the series combo of 12 and 5 pf vs. 10 and 5 pf.

The 10 pf across two 680k resistors goes to a connection that goes off the page to the right, so not sure what it is doing or how critical. I guess you could try 12 pf, or you could put a 56 pf (or 68 pf) in series with 12 pf to bring the total closer to 10.