What is your "go-to" primer for Baltic Birch?

Rustoleum primer and paint combo of your color choice.

I ALWAYS appreciate your input Dan! Thank you!!

More than welcome!!

Make sure you use a fine steel wool or sand paper between coats, for a nice finish.

Thank you....again. Much appreciated!!

I like Zinsser BIN, a shellac. Amongst PVA-based primers (which are also good) the Wall and Wood primer from Sherwin Williams is nice and generally accessible, though the equivalent from Ben Moore or any other real paint store should be fine. (The main secret to finishing: go to a standalone paint store. Tell them what you're doing, and buy what they recommend!)

For a really good finish on wood, use a grain filler first.