I ride a home built 28h 3X DT 240s front hub, Revolution spokes, DT RR 1.1 rim, black alloy nipples. Just as with a 32h, there are 4 groups of spokes, an inbound set and an outbound set on each side. With a 28h wheel there are 7 spokes in each group instead of 8.
If the hub has high flanges there can be interference on the flange at the spoke head area (partially overlapping spokes). In that case 2X should be used instead of 3X.

Al