(Not an answer, but an amplification on this question.)
The US National Kubb Championship Rules (v2) state in I (C):
The king is placed upright in the center of the pitch, and the kubbs are placed on the baselines (short edges of the rectangle), 5 kubbs on each side equidistant from each other. Kubbs starting the game on the baseline are referred to as base kubbs. The baseline should run through the center of the kubbs.
There is a picture along with it that shows the suggested layout. A cursory review doesn't highlight any other references to this. I find this part of the rules lacking.
When I play I tend to simply place the baseline kubbs equally spaced on the baseline. So I have six equally sized gaps (0.83 m) between the stakes and the baseline kubbs. At nationals this year they were spread wider, closer to a baton length from the pins and then equally amongst the five. In our final match at Nationals the team we played placed them exactly 1 baton length from the corner posts and I suggested they were a bit "wide", to which they flatly refuted it was completely legit.
The way I read the rules right now, disregarding the picture, it seems like I could place all 5 kubbs within a couple feet of each other in the center of the baseline. Technically that would be fine with the rules (although it clearly is not what the acccompanying diagram outlines).
It would be nice to have this clarified more, or possibly just standardized to 1 baton length and then equal spacing.