[PvK]

1) Whatever values you choose for each ability modifier, should be in line with the point costs for directly improving those abilities.

2) There is no way to mod a point value for culture settings, unless you can get your players to understand that they need to alter their total expenditures based on the culture they choose.

3) Consider that you can balance bonuses to desirable abilities by combining them with negatives to other desirable abilities, and hopefully ones that make sense for the culture described.

4) Realize that some abilities tend to me maxed or minimized, and some don't, and realize cultures can be used to extend the limits, and/or the threshold point, and adjust costs appropriately.

5) See Proportions mod (and soon, PvK Balance Mod) for an example of adjusting all of the cultures so that they provide a net zero advantage, compared to buying the same abilities directly.

PvK