That ribbon book sounds amazing. :)
It's amazing how much the type glue actually does make a difference, both in how easy or difficult it is to use in a certain scenario as well as the final result you get from it. Factor in that different types of papers have different textures, thicknesses, etc., there really is a lot to experiment with. Out of curiosity, have you tried the spray adhesive? What kind of luck have you had with it? I've been tempted to try it myself, but I think it would be too messy and unwieldy for how I work. That said, I did decide to switch to spray varnish to finish my pieces because regular varnish keeps on fucking up my brushes and it was getting wasteful. Remind me to share the results of that.
I'm mostly coming down on the side of "going to take way too long to pay off."
Sorry. Tangent here. That's the hard thing about making things to sell, isn't it? You need a product at a price that someone is willing to buy, but at the same time you can make enough money off of to make it worth your while. No one wants to do the math to find out they're making less than minimum wage on each piece they sell. There was a really good thread on Reddit a while back about people getting worried that Etsy is starting to ruin the market value of hand made products because A) people are willing to sell stuff for less to just move product and B) people are selling handmade goods from Asia for super cheap (I kid you not) bringing the price of stuff down. It's a pickle of a situation for sure. If your amaze balls quilt could have easily sold for $3,000 ten years ago but now people think they should only have to pay $500 for the same quilt today, you're probably justified in feeling a bit frustrated.
With that in mjnd, how's your Etsy shop doing? Have you tried to figure out ways to make more books faster, cheaper, etc? I'm genuinely curious. :)