Chad,
To be honest I never thought when I got into this that drawing and shooting that much weight would be possible or comfortable. I really didn't but the more I shot and shot and shot it got easier and easier and easier.
Seriously, 62.5# at my draw length feels like butter to me. (I'm a moose of a guy like you ) But even being a big strong guy it took a little til' the muscles adapted as well as the fingers. Now that they have the weight feels almost "light" for lack of a better word.
I can hold draw for 20 seconds or more and still make an accurate shot.

I know what you mean about arrow flight, that's one thing I brought over with me from my compound 3D competetive side. I wanted the best possible tune I could get and man do I have it. You should see my bare shafted arrows flying with my finished arrows at 200fps. They look like bb's leaving the bow and impact absolutely no different than my fletched ones. Standing at the line you can't tell which shafts are which in the target by looking at the nocks.
For giggles I paper tuned it at various distances and the bare shaft holes look like I shot them with a gun.
I have the same tune on the longbow. I was expecting a nightmare getting arrow flight that I was happy with and the process was simply enjoyable and turned out great. I loved the cause and effect of it.

As for worrying about speed.......not in the least. Maybe if I start to compete in 3D with either bow I'll mess around but that 640gr arrow tipped with the 220gr SS Muzzy Phantom will be humming along just nicely come deer season. I knew I wanted a finished hunting arrow in the 10-11gr / lb range and that's what I ended up with and everything just fell into place nicely.

I know my limitations and am in it for the challenge and the overwhelming tug of the romance of it, but I still like to see what the numbers are even if it's just for a base of reference.