Thanks to googlebooks, I was able to track down the source of yesterday's photographs. The inside of the flier, shown above, gave me some keywords to look for. The tricks described were from Ovette's performances, and it goes back to the "Free Guessing Letter" I scanned back in May.
A few of the pages from the scan of the book are below- it pretty much just copies word for word what I have in the ad, and republishes the picture from the front of the pamphlet.
Looking at this photograph of Ovette from Magic Nook, I am going to weigh in with my opinion that it is him in the photographs. And judging by the hair on his head, I am also going to assume this ad was from at least the 20's if not earlier.
The back page has some hand-drawn illustrations, and I will share those tomorrow!