Most of those have decent discounts, particularly in advance. That said, many of them also have lotteries, so you could try your luck and as soon as you know you didn't win, just buy them using a code online or at TKTS.
Also, not sure how crazy the Hamilton cancellation line is these days, but if you're arriving on Friday, I'm not sure you be getting to see that Friday night, as many people are still queuing up pretty early at like 6 a.m. and such. So... you may have another opening on Friday.