I think the only thing I'd be concerned about is knee. If you feel a pain in it, you really should let it out, and then try again after it feels OK again. Do this as often as you have to, try to find a better position each time. There's really no good reason to try stick with something that will lead to an injury.
I'm not talking about the soreness after you've sat for a long time, which I think is OK, but a twist in the knee that is caused by inflexibility in the hip... which would be noticeable fairly immediately if it's a serious twist, or after a few minutes for a more subtle twist. Never
try to force your knees like this, or they'll end up ruined eventually.
Also, if the numbness becomes too uncomfortable, and your attention becomes agitated, I think it's really OK to just let it out. If you can't focus, I think that kinda defeats the purpose.