As far as the sound....As spring is being compressed but the sound your hearing makes me wonder if you have a dab of grease on the pivot ball of the clutch fork. If that dried out while you replaced the clutch then you will get a small creak kinda like the creak you get when you step on a bad wooden staircase only quieter.

Under heavy accell I would say to bleed your clutch system a little more. It sounds like the trans is still rotating too fast to get the outer slider to move. There are metal ball detents installed between the inner and outer slider of each gear selector to prevent you from trying to shift while still engaged. I think this might be your problem.

Torque of slave is not the issue. few pounds isnt going to make any difference.

Terry