Keep your 1-31 entry points near the 0 entry point, and the 33-63 entry points near the 32 entry point. These two are the 'main spawn' areas and the distances are checked against these. Also, try to make your maps have a central spawn point for attackers and one for defenders, usually having 360 degree spawns around a castle doesn't work too well. The spawn code in crpg (which is from native) takes height into consideration (walls for defenders) but this doesn't always fix it.
The spawn points are not split down the middle and it is usually distance that is checked, which means siege maps cannot be too big or too small (well small ones work as long as each side gets their spawn area). I'd suggest taking a look at the native scenes (don't pay attention to the numbers because they are wack) for placement options.