Actually Folkways' 10"s proceed the 12"s. There was a short time (late 40s - early 50s) where the record industry didnt know what the full length format would be, which is why you see not only 10"s & 12"s from that period but so many 7"s box sets. Yes, some - Capitol being the prime mover here - thought that 7" box sets would be the industry standard! Liberty experimented with the multivolume 7". Martin Denny's Exotica, for example, was issued as a 2 Volume 7" at the same time as the 12" release. A lot of jazz on Prestige, Savoy, and other classic jazz labels went to the 10" long play format because it was the logical extension from 78. I mean, why waste the pressing technology. After the industry shifted to 12", many of the the cheapie labels like Royale continued to do 10" because they could get them done at cut rate. Folkways did the shift to 12" when the rest of the industry did, though there is a 2 year transistion period where they released both formats at the same time. This was done for market reasons not length or what they had available (most folkways releases, especially the field recordings, reflect about 10 - 25% of what was actually recorded). Most of the 10" were later repressed onto 12".
Down Home Music in El Cerrito, which is run by the guy who does the Arhoolie & Folklyric labels, used to have all the Folkways albums. It was very impressive to see a whole wall of them. To have them within listening reach must have been great.
Ernie B's is great. I've been ordering records from him for years and my brother is good friends with him The guy is now the largest reggae distro in the world. He started it because he couldnt find the records he wanted and had friends who couldnt get them either so he would buy batches - sight unseen - of old stuff and get boxes with records literally thrown in them. He would get a box of 45s of 100 different titles without sleeves, shipped in a box without packing material. The titles he got were so obscure and so one of a kind that he built a good rep as the guy to go to for obscure reggae, especially with djs (which is how my brother met him). Within 5 years he went from doing it out of his garage to having to expand. He really should bring his operation down to Sacramento and have a warehouse with a retail section, but he enjoy living in the hills and doing it from home. Anyway, very nice guy, great prices. I recommend culling through the 45 section as you can find some gems there.
I dont think the Chintz Devils was the last BoH records. The MeeMees LP came after the 10" and there was the shitty Trigger Happy Band 7".