Wheels don't taco from radial loads, and are incredibly strong radially regardless of the spokes or rim. (My front tubular wheel with a 300gr rim and 14/17g butted spokes once supported the the rear quarter of a car).

The tacoing the OP experienced was probably caused by excessive side loads. The rules for side loading are very different than for radial loads, and involve flexing the wheel to where the rim was so far sideways that it could move to the lower tension S or potato chip shape. This isn't as far as one might expect, and a decent number of new wheelbuilders experience the same effect while stress reliving their new builds by the lay-flat-and push-the-rim-to-the-floor method.

The key in preventing this type of failure is to reduce the horizontal deflection for any given load. And the way that's done is with more steel, either more spokes, and/or thicker spokes. A stiffer rim will help by handling the increased spoke load better, but that's secondary since it doesn't contribute significantly to reducing the axial (sideways) deflection. Also be aware that increased tension doesn't stiffen a wheel since the elastic property is inherent in the spoke and doesn't change with tension.

As I said originally, there's a difference in absolute strength and ability to last a long time measured in miles ridden, and the OPs max load/few miles needs are different from those of the normal cyclist.

To the OP, you can calculate spoke length using any of the spoke calculators available on-line (my favorite). You need to know the "ERD" of the rim, which is usually available on line form the rim maker. You select nipples according to the spokes' thread end. If you're using 14g or 13/14g spokes that means a 14g nipple. Note that you don't want to use a straight 13g spoke and 13g nipples, not because they're bad luck, but because the OD of 13g nipples is larger, and most rims aren't drilled for them.