...the only thing that has seemed to produce the results I want has been to proceed the piece of wood I want to plan with another piece of wood and then push it through with another that seems to take care of the problem.
The fact that this remedies the problem indicates that infeed/outfeed support is not the main cause of the snipe. If the board is long and unsupported it can push up into the cutterhead (through leverage) and the same thing can happen if your infeed/outfeed tables are slanted downward (this would automatically angle the board upward until the 2nd feed roller pushed the board down to the planer bed). If either of these were the cause, then feeding one board right after another wouldn't change anything. Another test to eliminate unsupported boards is to see if you get snipe on shorter boards that are well supported. You can eliminate the infeed/outfeed tables as the main cause by purposely setting them slightly angled upward and see if you still get snipe. I had a dewalt 12.5" planer that came with the infeed/outfeed supports angled slightly upward from the factory and I didn't have any noticeable snipe on it.
Contrary to what the highland woodworking article states, another cause of snipe is that the cutterhead does move/deflect a very small amount when there is a force exerted on the infeed/outfeed rollers (from the board). As the board enters the planer, it first hits the infeed roller which will raise the cutterhead assembly a tiny amount, then it hits the cutterhead which starts cutting at a given thickness. Then the board hits the outfeed roller and raises the cutterhead a little more and the entire "middle section" of the board is planed at a nice consistent thickness (slightly greater than the first few inches of the board) until the trailing end of the board is no longer pressing against the infeed roller which causes the planer to fall slightly causing it to cut a tiny bit deeper just as it did on the leading edge.
Although there are sources saying that the cutterhead does not move, this is the only mechanism for snipe that explains why feeding one board right after another eliminates snipe on all boards except for the very 1st board and very last board. All the "middle boards" had both feed rollers engaged and therefore kept the cutterhead at the same height.
Another piece of evidence that supports that the cutterhead does in fact move slightly when a force is exerted on the feed rollers is that many people are able to reduce snipe by REDUCING the spring tension on the feed rollers. If the cutterhead truly didn't move, and all snipe was caused by the board lifting, then snipe should be improved by INCREASING the feed roller spring tension not reducing it. A higher spring tension should hold the board down more firmly to the planer table. Reducing the feed roller spring tension reduces the upward force exerted when a board runs through the planer, less upward force leads to less deflection of the cutterhead. I have improved snipe on my grizzly 15" 4 post planer by reducing the spring tension (a recommendation from some users on this forum).
http://woodgears.ca/jointer/planer_snipe.html
Do you have a locking mechanism on your planer? Do you use it?
Sorry for the long rant. I have spent too many hours thinking about and reading about snipe when I needed to adjust my brand new Grizzly 15" planer which had pretty bad snipe when I first got it. It was an upgrade from my Dewalt 12.5" planer that didn't have any snipe issues...
Jeremy