Originally Posted by
Retro Grouch
Rounding up makes the wheels a little bit easier to lace. Rounding down means you will be less likely of running out of spoke threads as you bring the wheel up to tension.
This is a nice summary. You can generally get away with being off by a millimeter or two in either direction. I prefer to round down. The rims you're considering are shallow enough that lacing shouldn't be terribly difficult. It's hard to beat the Rose Bikes price for spokes of that quality.