Okay, there are 2 different mating surfaces to deal with.
The fit of the spigot into the head recess seals the compression.
The gasket seals the oil.
So, take off the head and gasket, place the head back on by hand and push it down as far as you can by hand. No bolts. No gasket in place.
Take some automotive feeler gauges and measure the head gasket gap in at least 4 different spots all around the head. Write down what the measurements are. If the head tilts one way or other, the spigot needs to be filed flat to make the head seat evenly all the way around. It also needs filing if it has irregularities on the top of the spigot where hot gases can blow out. Don't file any more than needed to clean up the fit, and don't let filings get into the engine
Put the head back on by hand again and measure the gasket gap again. It wants to be around .025" gap. If it is more than .025" -.027" then file the spigot down until you get that size gasket gap. If the gap is too small, then get the top of the barrel skimmed down(making sure they know to not cut the spigot) at a machine shop by the necessary amount to give that .025" -.027" gasket gap.
The stock head gasket is a copper/fiber/copper sandwich type gasket, and is typically about .035" thick. When this gasket is in place it holds the head about .010" too high, but it can crush about .010". So, when you torque down the head(20 ft- lbs) it will crush the gasket down enough to seal the oil, and it seats the spigot fully home into the head recess to seal compression at the same time.
It is important to get these 2 planes of sealing done simultaneously when the head is torqued on.
Once you do this once, it won't leak, and you can change head gasket(same stock type) any time and still have it perfect. The only time to need to re-do this is if you get a new head or new barrel.
If you don't it this way, you have a strong chance that you will fight oil leaks or compression leaks for the life of the bike.