Tyler Joseph Hi Tyler!
Congrats on getting started, and welcome to the community!
As for your comment about acquiring multiple pieces of land, I would say don't put limitations on yourself. Keep in mind a big part of this business model is low risk, high reward, so if you come across a lead for a property you can buy for $2500 instead of $1000, but can sell it for double or triple cost, you make more money. It takes the same amount of work to get a deal done, the difference between deals are the dollars signs on them.
With that said, I have experienced similar problems in my lists, and have utilized Virtual Assisstants to get around it. I'm guessing if it's an incomplete list, it means less competition, which personally always gets my gears going. I'm assuming there is a county website where you can look up an individual property by parcel number. This will then have all the fields and descriptions about the parcel, often GIS mapping, and many more details.
Write out a detailed instruction document with the link to this website, and pay a VA to add the fields of both acres, and improved land value. That's what I usually do to make sure I am working with vacant land and I know how much. They will only cost an extra $20-$30 on Fiverr, but I promise they are well worth their money. If they save you from sending mail to 40-60 people on the list, they are basically free! Any more than that, and you are making money by using them instead of just mailing out to the list you have received.
There are probably more strategies to get around this, but this is my personal one. Best of luck Tyler!