During my ride today I observed other people on the bikes. I get the impression that my bike's crank arms are longer than theirs. One of the guys, when at the top of the pedaling cycle, his lap was still some 45 degrees angle to horizon. Mine is just a little short of being horizontal, and my leg-to-torso length ratio is greater than average.
The overall length range of standard adult crank arms is 15mm, from 165mm to 180mm. That translates to roughly one inch in diameter difference in 13" average. I doubt you could see that at any distance.
Please don't be offended but I believe you're obsessing over nothing. Saddle height isn't rocket science. Put your bike near a wall, sit on it, and adjust the saddle so that without rocking your hips, or reaching, your heel rests on the pedal top lightly with knees straight. When you pull your foot back so the ball is over the pedal spindle you'll have some natural bend in the knee. This isn't super precise, but is very close, and you might opt (if you had a reason) to tweak it up to 1/4" either way, but very rarely more than that.
Worrying about the "lap angle" is misleading because you can't gauge yours yourself, except by looking at a broadside reflection in a mirror. Actually one of the best ways to gauge your own riding position is exactly that. Ride past shop windows and look at your reflected self.
As for knee and hip pain, they can be from a poor saddle, foot twist, which is a common problem for those who naturally walk in a toe-out foot angle. Some people also benefit from wedges which roll the foot to one side or the other, but this requires knowledgeable fitting and expertise.
IMO, if you're over 5'7" tall with normal proportions, you should be fine with standard 170mm cranks. If taller you could ride longer cranks but don't need to. Get a basic fit as I described earlier, ride your bike enough to get used to it, and don't sweat precision fine tuning because it won't make a difference.