Have the discipline to NOT buy properties that don't pan out when due dil reveals material problems.There are probably properties I didn't buy that would have worked out well.  

If you ever need renderings for marketing materials, I would love to help out in exchange for learning more about your process-Natasha

From dealing with contractors who attempt to take your kindness for weakness and order more than needed material (for there own use), to unforeseen issues with a property's structure, proper budgeting and the list goes on.

I am looking to make a rule of thumb of when each material is used.I've installed around a hundred better-quality, custom-fit vinyl windows so far.

For MATERIAL?

Jim's material is not junk and he's a stand up guy from what I saw, however a real estate investor he is not from what I saw.Strong words?

Since I really don't know much about the railroad industry, the first thing I would do is research what (if any) regulations exist regarding what can be transported via train through residential areas.Not only do you have the concern of kids playing on the tracks, but the potential of derailment with hazardous or flammable materials. 

This will give you insight into the professionalism of the work, as well as the caliber of materials.  

But if the boards are a little warped, they should relax and flatten on their own after some time.Question: Did the installer let the material acclimate to the room for a couple of days before installation?

If you are soliciting unknown people you need to look at syndicating and learning about that first.Any promotional materials you would need to read Bigger Pockets rules and learn about becoming a paid member and posting in the marketplace section.Thanks