How to Default Config Property Based on other Properties in Configurator

Dear All,

We have requirement wherein we have to default a property called Swing Weight. It is based on combination of other properties.

We have 8 models and for each model we have around 3000 combinations.

Head Model, Shaft Model, Head loft and Shaft Flex are Inventory Catalog Properties.

Can we achieve this without extension rules?

Client requirement is to default the value but there is a possibility that they would change it, so users will be allowed to change the default value in the LOV.

Any Inputs in this regard will be of great help at this moment. This is bit urgent.