Determine value on raw land with permits in place.

[Clayton Smith]

I purchased a 5 acre parcel of land with a single family home this year in the middle of my town. I am working with the city to get it rezoned to develop this property. I will go in front of the zoning board next month with my plot plan. As of right now I will be able to fit 38 town homes on the land. They will be side by side duplex style townhomes. The ARV for these will be $225-$250k each after construction. With the location being close to the University of Alabama there is also a possibility for the buyer to build these to rent for $1800-$2000 each. I am looking to sale the property and realize the gain instead of staying on for construction to a finished product. I listed to "on the market" and James Daner said that land typically sells for 20-25% of the ARV. But my question is how is the best way to value the land? I am thinking that in my market I should take no less than 15% of the ARV for the land. I do not plan on doing any of the land development. Just selling the raw land as is with permits in place so a builder can get started the next day. How should I determine the value? Should I pay for a commercial appraisal to make sure I list it for the right price?