sysctl vs kernel .config

[Jim Green <student.northwestern@gmail.com>]

Hello debianers:
today i successfully compiled 2.38.4 kernel using make-kmkg and fixed
the hibernate can't resume issue for kernel 2.38-2, got a couple
questions here:

first is run time and the latter is compile time, but what is the
difference here, is one of the other's subset? do their parameters
overlap? which is the preferred file to change? changing .config
requires a recompile.

Thanks!
Jim