This particular stream taught me everything there is to know about getting my landscape materials put together in a good fashion. Andrew Hurley even gave a great template material layout that i still use today. It uses height blend which you mentioned you were interested in. It does provide the smoother blending than a weighted solution, which is nice especially if you are doing the work using the landscape tools versus an outside program.
In addition I would also check out the technical guide, https://docs.unrealengine.com/latest/INT/Engine/Landscape/TechnicalGuide/.I had a similar problem with squares and it turned out my choice of quads, sections and components did not fit well. This played havoc with my texture resolutions. The guide gives some great suggested sizes that are a good rule of thumb and fixed my particular problem i was having.