Erik and Ben,
much thanks! i took both of your ideas to complete the task...
couldn't find a spark plug big enough to plug the O2 hole, so i cut the old one down to be able to remove it. it took a vice, a 22mm box wrench, and a hammer to finish extraction.
next, plugged the hole w/ the old remnant. ordered my denso and anti seize grease. fastened both sensors JUST snug until the grease arrives. next time should be easier...the after market assembly is O2 friendly in regard to access.
thanks again!
btw...1-2 day shipping was just over $1 more than reg ground