Partition Size: Setting It With An Actual Numerical Value: Possible ?

Hello,

When I installed W10 using Parallels on an iMac, there was a screen that came up with a Slider
that apparently asks about making the partition size.

No number options, just a Max, Min., etc. mark on the slider.

If I want to actually put a number in for the size of the W10 partition I would
like, is there any way of doing it ?

Any way of knowing what the program actually put for the W10 partition size ?

Thanks,
Bob