I would say if it doesn't rotate freely, then however much runout you have with those particular parts is too much.

I'm pretty fussy about main runout...... I really like it less than .001".
I have let it go with a little more than that, but only if the crank rotates really freely.

How straight and parallel the main bores are, along with the alignment between the bores, along with the bearing clearances, will determine how much journal runout any particular build can safely tolerate.

Be sure to check all 3 of the center journals.