Hi agilebda. Seems that you are pretty meticulous in your effort to do the job right, so here's a couple of other things you might want to do. I would suggest you de-carbonize the head. Open the valves and clean the seats good, with a product such as C4 or other de-carbonizing agent. No scraping. If the engine has been run hot, even for a short time, you might want to check the head for warping. This can be done by finding a known 100% level surface, large enough to tack, tape or staple a sheet of 1000 grit water rub down on it. Lay your head down on it with chamber dome down and with light pressure, make a oblong circle three or four times. Then wipe the mating surface off good and inspect it thoroughly. I use a lamp with a magnifying lens attached. The swirl marks should cover the entire surface. If an area is found with no swirls, then you have a warped head. (very old school, but it works every time.) While you are doing this inspection, also look for hair line cracks or any etching. Anti-freeze and hot exhaust gasses both can destroy a head, especially aluminum. Chances are more than good that you will have none of these conditions, but it only cost a few minutes to make sure. Good luck and keep us posted.