Spoke Size / Spoke Length Database - What size spokes do I need?

I had a nightmare with my last wheel build, was using a set of hubs which were meant to be Shimano Golden arrow but they had grooves to guide the spokes along the flange. I calculated the spokes for a 3x but the spoke guides won't let the spoke reach the hole they should. I reckon they're designed for 2x lacing which is odd!

I'll get pictures up later.

If it was a 28 spoke hub then 2x gives the best angle.