As a long time location sound recordist, your comments about Lav's being fine, and boom as backup is the worst advice you can give anyone 'getting into' production. Relying on Lav's, renders you what we have here, the typical claustrophobic amateur feel to a video. Brings the video down. I understand this is for blocking training, but in any case, Always boom and use boom unless it's absolutely neccessary to pull from the lav track. Audio is usually the biggest let down in all B grade / indie productions, a good boom track can transform a performance and save a scene....
Awesome video on blocking though, learnt a lot from it :-)