To fight bubbles embedded in the casting I got a spray bottle to apply VacuFilm on the wax models more evenly - this worked and I got a thin mist layer instead of large drops as when using the brush.
I also got a new vacuum chamber for degassing before and after investing the wax model. I tried to do that with the vacuum oven for a long time (it was large enough), but after using it for wax, it no longer pulls full vacuum unless it's hot. With the new chamber, time to full vacuum is short enough that I can vacuum twice, all while agitating aggressively with the vibratory tumbler.
The resulting casts no longer have bubbles stuck inside concave geometry. There are actually a few bubbles on convex geometry (perhaps just a spot I missed with VacuFilm) but those tend to be simple to just grind away.
The last problem are the inclusions - and I noticed that making sprues that are bent several times before reaching their target may be the answer. The model that had two of these bends next to each other had the least inclusions of the entire batch (almost perfect).
I automated the investment/water weight calculation to save myself some time & trouble. I wanted to experiment with Preact and Recompose for a while for building small but potent web apps, and also to see how simple it would be to build a site that's pre-rendered and hosted in a static S3 bucket on the Amazon cloud even though it was using all the features of an advanced view engine. Publishing it on AWS was super easy - now I am taking a UI design class and learning Sketch to design the graphics to go with the functionality.
Of course I will mostly be using it on my phone, so I have the mobile comp as well.