So when I manually turn it over as soon as the mag snaps I then gauge them both or do them individually as it snalp?
It's not critical. Anywhere around TDC will work.
Think about it. At the beginning of the compression stroke, both valves are closed. If they weren't, mixture would exit via a valve, rather than compressing. Same with the power stroke; if you open the valves too soon, you're not getting all the energy out of the combustion. So you have both valves closed for a substantial period of time before and after TDC.
Just turn the engine until TDC. mic/set both your valves. Don't be turning the crank while you're doing that. Once you're done setting them, it doesn't matter if you turn the crank, and you can button up the covers at your leisure.