@Julio Vasquez where are you generating land leads from? Do you do SFR's and folks are saying "I've got this land over here that I don't want"?
I can tell you that as a land investor I know folks who work in the AZ area, it's super competitive for land investors and they need to be acquiring the land around 25% of the "for sale" like kind property. Make sure it isn't land locked (it has direct road access) and you'll have yourself a deal that a land investor would pay for.
As for your thoughts on how to value the land based on highest and best use, I'd say that most land investors are flipping and not improving or splitting. The returns are better to buy low sell high than they are to buy and wait for timely subdivision or improvements. So you're either going to sell to a land wholesaler quickly and easily or to a developer which is more difficult because they're harder to find.
Go on LandsOfAmerica.com, sort by price and map the area where your lot is. The first 3-4 people that are signature members are going to be land wholesalers. See what their cash price is and if you can get it to them for 50% of that you can keep anything else and everyone wins. So if the cheapest lot is 9k cash price, and you get it under contract for 3k, you can probably get it to the land guy for 4-4.5k and make 1k. Those are the margins they want so if it's not 25% of for sale or 40-50% of the signature guys' pricing it's probably not worth your time or theirs.
Hope that helps!