I did use the heat setting but I also started with warm water from the tap. I cleaned several batches of stuff trying different time settings. It seemed most of the corrosion was blown off in the first 15 to 30 seconds -- I was surprised.
The jet was from the first batch which included many little parts. The float needle valve assembly was the last thing I cleaned and I cleaned it by itself. ( Actually I pulled the plunger and spring out of the end of the needle so there were 4 things being cleaned and stuck it back together for the picture.) IIRC that was 180 seconds worth of cleaning but I doubt the last 90 seconds did much.
The stated ratio of 1:4 SG to water is more of a guess than an actual measurement, or even estimate.