You did a great job on the bag. I am in the process of making myself a TM bag. It is looking a little gaudy, but it will definitely be one of a kind. The only thing I would add to yours is a pair of lips embroidered in red.
I have followed the same instructions you used and had the same problem. I believe as the oil heats up it congeals and causes more problems. I have used soapy water on my cast iron with no problems. I season my cast iron by washing it with hot water. I dry it then heat it on the stove until very hot, remove from heat then pour on olive oil. I let it cool. I have also done this on a grill outside. I found these instructions online many years ago, the explanation given was that the heat opens the pores of the cast iron and as it cools, it traps the oil. Don't know if that is true but it works for me. I have bought cast iron that was rusty, scrubbed well and used this method with good results. Other oils can be used, just make sure they are appropriate for high heat.
For class we were given a project to make an x-ray circuit. Since I had to spend money on it, I decided to make something I would use.
We had to make the electrical circuit of an x-ray tube. The white fabric under the flap has the circuit on it. The front of the flap is basically what the x-ray unit in class looks like. The upper potrion under the flap is my version of the x-ray tube. There are no pockets or anything. It is just a bsic tote.
You could try replacing the waistband. Get a pair of jeans from the thrift store with a waist band that fits. Remove the waist band from both pairs of jeans a replace the small waist band with the one that fits. For a quick fix, get a small ponytail holder, round stretchy kind, hook onto button then thread through buttonhole then place back over button. Works great for those bloated days also.