I have to apologize for post #15 I had second thoughts(often a bad idea) and changed my initial correct response to a wrong one
at TDC compression, both valves are on their seats and yes the rockers will wiggle by the amount of lash you have set
Here's a valve event diagram for S cams that I put together, E will be similar but w/ less lift and duration
TDC for each cylinder occurs twice in 720° of crank rotation the first is at TDC compression which I have arbitrarily labeled at 0°, the second is at TDC exhaust which is at 360° where both valves are off the their seats, it is this overlap that allows properly designed headers to extract additional power at specific rpm due to exhaust resonances