When people say that size doesn't matter, they are dead wrong when it comes to riding a bike downhill. Weight doesn't make you go any faster is only true if you didn't have to deal with drag. When you factor in the drag, heavier guys DO go faster.
In a real tight tuck with my chin almost touching the stem, my hands next to the stem, arms folded in front of my chest squeezing together what little I have there, and my knees touching the top tube, again folded in, I still get passed by men on downhill. I just don't weigh enough. It doesn't matter even if I sprint out of the corner... There is another trick to reduce your frontal area but it is really dangerous and its banned. Even then, guys would drop me on downhill.
Also on a fast downhill (40+MPH 60+km/hr), drafting will make a difference. The person on front gets help because the wind shadow which he creates behind him act like it is tugging him from the behind. With second person behind him, that wind shadow moves behind the second person thereby effectively removing the wind shadow from the lead person. The lead person only has to contend with "cutting" through the air only. The tugging by the wind shadow is then taken care by the last person in the draft. Everybody gets to go fasterBit scary though when you are literally inches from the person in front of you at 40+MPH downhill.
As for power meter, it is good on a trainer. Not sure if it is worth it on the road training. And yes you do have to exert a heck of lot more at higher speed. going from 15 to 17mph isn't too bad. but trying to go from 24 to 26MPH is much harder.
besides, power taps are $$ ... and I've learned to free myself from being a slave to numbers and fancy hi-tech measuring equipment. I'm not rich to be flounting hi $$ just to say I can (like the time I saw a peron on a fun ride with Cervelo P3C with vision tech bull horn bars... the whole 9 yards. gawd it must have been really comfortable on a fun ride![]()
smilingcat