There are two things going on in your initial story. The first is bolusing for the mini cannoli, how much insulin and how much ahead of time to pre-bolus. You are going about your experiment in the right way, and can make small adjustments to what you tried to see what gives the best practical results. In general, when eating if I have an early excessive high followed by a later low, there was too much total insulin because I went low. But the excessive early high says the digestion of the food ran faster than the insulin action, so I needed to pre-bolus earlier to give the insulin a bigger head start so it could keep up. So for a too-high peak followed by a low, I’d try a smaller bolus given further ahead of the eating.
But there’s a second thing at work in your story. You exercised (by walking) while you still had the active bolus in your system. That’s actually a good thing, but it affects the insulin dose because exercise makes the body more sensitive to insulin. If you had bolused exactly as you described but sat on a couch instead of going for a walk, maybe your BG would have stayed high rather than dropping to 65. To learn how to adjust insulin dosing to handle exercise, it’s just more experiments to figure out how it works for your body. If you’re looking for inspiration, you could read daisymae’s swimming thread to see how she started with wild BG swings and fear, and experimented her way to a real mastery of dosing strategies that work for her body. Daisy Mae's swimming BG thread
The way to deal with being conflicted like this is to run the experiment. Of course this means you’ll have to eat mini cannoli’s again and again, but if you are willing to make that sacrifice it should be possible to figure out a strategy that works. Folks here will offer suggestions if you describe what you did and what happened. The nice thing about figuring out insulin dosing is that you have as many do-overs as you want. And you can say that you’re eating cannoli for science.