Directions from the net is often for HD rims. Indian rims are laced mirror reversed as the drum brake is on the opposite side, best is directions in the R&O but in a pinch, a HD rim picture can be flipped over in a computer. If you put the rim down with the tube hole against the floor, Indian rims has the first forward spoke hole to the left, HD to the right. However, rumour has got to my ears that it has been done before, lace up a HD rim on an Indian and get it close enough. Ugh!
Original there is a difference between front and rear rim tit angles for the spokes, maybe not all that important if that is not on the repro rims and the nipples has room for the lean angle.
Lace the brake drum with all the spokes threaded from the outside like in the picture.
Indian did thread half of them from the inside, but only for a very short period in the beginning. I suspect that showed to make the lacing weaker, with dual bends on the spokes more prone to losing up spoke tension if the rim on the brake drum sagged the least.
Actually Maciek carry 2 version drillings for different spoke versions, one drum drilled for the earlier clincher wheel and drop center rim, and then the -31 version with its thicker spokes. Maybe it is so that you can order a 3rd version for the earliest spoke pattern if you wish, the one with half of the spokes laced from the inside.
The drum versions can be decided on old drums, by where the countersunk for the spoke butts are drilled, sometimes wear from the spoke stems also is visible. That earliest version has half of the holes countersunk at the inside and half on the outside, but most has all countersink on the outside. Some of the drop-center rim drums are drilled in a zig-zag pattern but the -31 drum has larger holes and always drilled in a zig-zag pattern.
Obvious perhaps but, the opposite side hub rim, and the rear wheel hub rims are always laced half from the inside and half from the outside.
