Well, I'd hate to be the one to tell you but you've already compromised their sonic characteristics by placing them in a cabinet. So, orienting them side-ways probably won't matter much. I'm not a fan of enclosing speakers in cabinets, ceilings or walls.

You may want to experiment with tweeters in or out to see what sounds best.

House of the Rising Sone
Out in the mid or far field
Dedicated mid-woofers are over-rated