Thanks to all for the help on the screw sizes.
First, I wasn't sure whether they were metric or English. Is there a
general rule for the Roadster as to what areas have which?
Second, the screw holes were corroded and rusted, in some cases tapped
with a metal screw, and generally difficult to identify.
But it appears that the tiny screws on the drive train hump and the
radio console are in fact #4 - 40. Not #4 - 36 or a metric size as I had
first stated. #4 - 40 are easy to find. But I agree with a couple of you
on the wisdom of using the tap tool. Some will have to be re-tapped
anyway due to being wallowed out. So some are going to get converted to
#6 - 32! On an attractive metal screw :-(
'67 1/2 1600, runs good but in need of body work!