1) Divide Living Space/Lot to get HF(House Factor)
2) Subtract HF from 100% to get LF(Lot Factor)
3) Divide Sales Price/Living Space to get $/sq ft (House)
4) Divide sales Price/Lot size to get $/sq ft (Lot)
5) Multiply $/sq ft(House) x HF(House Factor) = HV(House Value)
6) Multiply $/sq ft(Lot) x LF(LotFactor) = LV(Lot Value)
7) Add HV(House Value) + LV(Lot Value) = HPM(House Price Multiplier)
Also, this will give you an idea how much the House and Lot is worth individually. The HPM (House Price Multiplier) is to be used as a baseline or index for original houses on standardized lots. Sales Price will take care of the Location Factor, but you may have to adjust slightly for building materials, view, traffic, uneven lot, etc.
Since most of the value is in the land here, what do you think?