When trying to pick apart someones post, please have a clue about what you're talking about. The difference in weight between the tubular version and clincher is around 270 grams, that additional weight is all at the outside edge of the rim (hubs and spokes are the same). So along the lines of what the other poster has tried to tell you, the weight difference is actually closer to 20%. The effect on rotating mass is very significant (do you understand what rotating mass is?)
In short 300 grams saved at the edge of the rear wheel, is worth massively more than 300 grams saved anywhere on the bike, your mention or rider and bike weight means nothing, we are comparing a clincher and a tubular version of the same wheel.
An anecdotal comment now, there is nothing in the world that would make me want to change from my tubular version of the wheel to the clincher when coming in to the finish straight sitting in the front group of riders ready to jump and sprint for the win, somehow from the tone of your posts I don't think you get to that position too often.