I've been making tempeh frequently for many years (maybe around 1986!?) I've basically followed the directions in the old "Book of Tempeh" from the '70's and pretty similar to what you do. Usually I just trample on the soaked, briefly cooked beans in a bucket barefoot to separate the hulls and break the beans in half, and then slurry them off with repeated rinsings. I often pre-ferment mine then, in a pot with water to cover and set somewhere warm for 24-48 hours more....sometimes I add a bit of kefir, homemade wine, or sauerkraut juice to this as s starter. This prefermentation naturally acidifies the stuff so you don't need to add vinegar, and it can improve it's nutrition also. Then I boil this up for 45m to an hour and proceed as you show. For an incubator I have small brooder heater in a cardboard box with some racks rigged over it....this has the advantage of a thermostat so I can basically set it and leave it till I think to check it. I have done pots of hot water in coolers and ovens and moving tempeh closer and further from woodstoves and things like that too. Been getting my starter from temephstarter.com direct from Indonesia...prices are good and several kinds available, but I also do my own starter and usually get several generations before it begins to degrade. Lately been playing with making it out of fava beans, since these grow easier in my climate....