I would try and repeat the test trying as best you can to ensure that the cylinder being tested is at TDC on the compression stroke (both valve closed). It may not be easy to confirm if you are on compression stroke but if you place the timing pointer to TDC and check both cylinder #1 and #6 to see if you can tell the difference in the valve/push rod it may help you know what the rockers/push rods should be like on #5.
If you get frustrated enough or just need to know what's going on inside pulling the head is a reasonable step although not free as you will need to replace several gaskets at a minimum.
