Clean the mold really well before using it to get their water soluble cutting lube off of it. Be sure the mold comes fully up to casting temperature before you start judging the size of the bullets coming out of it. For best accuracy, I find my 1895 likes bullets cast about 0.002" over groove diameter rather than the traditional 0.001" over groove.
You can, to a small degree, adjust the size of the bullets by "beagling" the mold. This is putting shims between the blocks to loosen the fit. The slight oval shape that results goes back to round when pushed through a Lee sizing die. The only issue with this is Lee makes only a 0.457" sizer in this size range. I had to saw a slit into a 3/8" dowel and put some oily 400 grit wet/dry paper in the split and wrap it around until it touched the sides of the Lee die. I then used my drill press with low speed belts to spin the paper until I started pushing out .4595's. I then switched to 600 grit paper followed by some polishing compound on a felt bob so I landed on about .460". It's a bother, but it can be done.
There is more on beagling not too far down the page in this article