leaking valve covers?

[Mgicm]

Have a 48 suburban with a monte carlo 305 in it. seems i am seeing a large oil puddle under it after running it in place for a bit. Traced it up to the passenger side of vehicle. looks like oil dripping where corner of valve cover is near the exhaust manifold to pipe junction and down over the starter. i put on a new set of covers - steel - and the gasket is new already. Still seeing some smoke when it idles...from the same spot.

What would next steps be? Check the covers for flatness? add a second gasket? Tighten bolts? Right now they are just snug for fear of doing more harm than good. Didnt use any silicone..should I? Looking for some tips.

thanks