Good thinking, Mike... another thing to keep in mind when adjusting the timing
is that the vacuum increases with RPM, and thus advances the timing further.
It's important that the engine be at the specified idle when checking and
adjusting the timing - on your car, depending on the exact engine, it should
probably be around 700-800 rpm.

Mike / Matt:
Thanks for responding.  History.  Bought used in 1994 with 55k miles.   I had
a good garage do the 60k service at 72k.  I had a schlock garage do the 120k
service at 140k.  I assumed that they did the coolant.  They did not.  It
went acid and killed the cooling system.  I replaced the radiator, thermostat,
water pump, and hoses and flushed the rusty water as well as I could, but too
late.  I cracked the head at 186k.  Got a rebuilt head and new pistons and
cylinders installed.  A radiator cap that could not suction from the overflow
led to coolant loss and a blown head gasket at 212k.  I replaced the head
gasket myself and blew out about 2 quarts of rusty crap from the block in the
process.  Very little carbon on the head (especailly number 1 and 2 where the
gasket blew).  The temp gage stays low even when blowing head gaskets.  Now
at 218k it runs great, but it knocks as always going up hills in the heat.
High octane gas does quiet the knocks.  To hit Matt's question, I checked the
timing at about 800-850 rpm.  It bogs a little when I check the no-vac
advance.  If I set it any more advanced than the maximum retard I can get, it
knocks worse.  Most of the time it runs fine.  It just knocks briefly if I do
jack-rabbit shifting or knocks pulling grades in dry heat.

Incidentally, I am replacing they front crank seal tomorrow.  Why did I not
do that with the new head gasket?  A mechanic convinced me that hondas never
leak from the crank seal even when they are bad.  I replaced the water pump
seal and oil pump seal so I think it must be the crank seal, so it's back
under the hood for me.  The timing thing still confuses me.

-Carlos