Earlier this year at 49yo, 5-9, 240lbs I did a 1:26.2 after rowing on and off, mostly in the context of CF-type workouts, for about a year. My only attempt at an all-out 2k resulted in a 6:56 and near-death. Not really near-death, but, for me, the 2k is way harder than any other distance. Kind of like how I've heard the 800 described in track. I've pulled under 1:30 in the 500 many times and again, for me, the first half or so is not too bad, then it's just hang on for 45 seconds. I figure I can do 'anything' for 45 seconds. Sure it hurts, but nowhere near how the 2k hurt.
As far as strategy, I've read a lot on the CII website that many rowers are way more efficient, even in the 500, with a relatively low setting/drag factor. I definitely agree for the longer distances and for rowing in general, but for the 500, for me, it's L10 and hang on tight. But, I realize that that part of it is very personal and L10 just won't work for some people. In my mind, and I know the analogy isn't perfect, it's kind of like cycling where different gears are more appropriate for different situations, but for a sprint you put it in the lowest gear you can while still maintaining a decent cadence. That works for me anyway. It's also really important, and this is mostly mental, to pull hard- no, make that even harder, not up to the end, but right THROUGH the end.
The only encouragement I've ever had is my wife yelling at me to come in for dinner, so I would love to try it in a group setting. Maybe someday at CF Vancouver or CF North...