In the early-eighties I was trained as a phototypesetter on Berthold equipment and I spent 3 years working full time as a journeyman typesetter while paying my way through art school (Yes, typography existed before the Mac). There is “good” and “bad” typography. Certain rules are adapted for a reason. The double word space proved useful for a fixed width typeface, but is not necessary for a proportional typeface. If you want to use two word spaces, then go for it. Be consistent and you might just pull it off, but a classically trained typographer will never agree that it is “right.” Just like we use a period to end a sentence and a comma for a pause, there are rules which help us communicate effectively. If enough people use two word spaces after a period it might just become the new standard, but this argument proves that that won't be happening anytime soon. Peace to all of you.