re: Lets Talk "oil finishes"

so I’m a bit worried now. I have a few sketches in my notebook of a table I want to build. It’s a sort of “maxi sofa table” so not too deep about 50 cm wide and 120 long. It’ll have three elm planks framed in mahogany, ….mahogany, elm, mahogany, elm, mahogany, elm, mahogany. I want to “frame” the elm. The two outside mahogany strips will be about a quarter the width of the elm boards (110mm), the two inner mahogany about a centimeter wide. The ends will be mahogany breadboards as wide as the elm and the whole thing sits on a mahogany leg frame.

All the mahogany has been reclaimed from an old church and remilled into boards. The elm is also very old and dry.

I was going to finish it with BLO and many coats of shellac…Am I going to have wood explosions? Should I consider poly instead?