A 3x 28h pattern is a true tangent, meaning he spokes leave the flange at a 90° angle from the diameter (or radius). This gives the maximum possible torsional bracing, and seems well suited for disc brake or rear hubs.

There may be a bit of a clearance issue as you lace since the spokes may pass over the heads of the crossed mates. It's not really a problem as long as you keep spokes loose enough while lacing that you can push them over to thread others, or load all the spokes in both flanges before bringing any out to he rim (my preferred method)

Or if you're considering a 2x pattern, you'll get a mall reduction in bracing radius. To know how much place a caliper (or improvised paper gauge) across any two holes on a diameter. Then place a piece of paper (or whatever) across the two holes one up and down from the end hole, and note the reduction in radius involved. I suspect it won't be great a all, but at least you'll have the info and can decide accordingly.