How do you determine the optimum inner and outer diameters for the lands
and clearance areas for a padstack with thermal ties to the power or ground
plane? A semi-newbie colleague asked me this today and I had to admit I
didn't know. Every company I have done board layout for has their own
standards, and there is wide variation in the sizes used. The spoke width
for all, though, has been a consistent .015".

The colleague I spoke of also looked claimed to have looked through the IPC
specs, but found inconsistency there, as well.

Any ideas?

Jay DeKing