One of the things I've learned is that I need to slow down my frame rate. My Nikon D810 is usually set at 6 fps to capture any sudden movement when I see deer or birds or even Harry's dog friends. Those always have sudden movements and bits are free, although I'm filling an 8 TB hard drive at an alarming rate. However, if I am intentionally doing multiple exposures, either a panorama or straight on showing subject motion, motion, there is not enough differentiation at 6 fps. Less can be more.
The other thing I'm seeing is changing the order of the layers can make a big difference, which I will illustrate another day.
I really like the last one, Andrew! The subject and colors really work. You're right about the order of layers make a difference. I've discovered that too!
Good to see you are experimenting further Andrew, each of these has it's own element of interest, but like Jennifer I find the last the most cohesive.
On the file size - do you flatten the image prior to saving? Otherwise files can be enormous.
Other than the lowest layer, I'm not certain layer order does really matter. But from my own experiments I find that the impact of layers is decreased from top to bottom given an equal opacity (eg if the top layer has an opacity of 5% then a layer further down may need to have opacity set to 20% to gain a similar result).
Moving layers in the stack can certainly give the results you describe due to this opacity phenomenon.
I have been struggling with an article I'm trying to write which includes this and other findings over the years, perhaps I can provide a draft if anyone would be willing to proofread and see if it makes sense.