re: vocal recording - I've done a fair bit of recording in my time (as a performer, not an engineer and in professional studios). I have always recorded vocals in a booth whether recording live or after the fact.

I definitely don't have a room anywhere in the house that wouldn't have weird acoustic artefacts without serious treatment, or provide "nice" natural reverb. I think I'm better off capturing a flat vocal sound and artificially adding reverb and EQ.

As for the foam, it is open cell. Truthfully, I'm not looking to recreate Abbey Road. These recordings are simply to achieve a good demo quality to be given to musicians to learn, then taken into a real studio and recorded properly. I'll never be, nor have the desire to be an engineer. I'm happier just playing and creating the music.