PB, I can't respond to internet photos 'cause I can't really see what's what.
First, most would be pleased with your first attempt and your second t-guard would look spectacular to many. I understand that your looking for a higher degree.
You need to determine when the metal is being acid etched beyond coloring. The slight frosting of the metal is probably happening during the time in the damp box. There is no perfect prescription; I determine when to card by visual inspection. It is all timing, temperature, humidity and RPM's, but seeing what transformation is taking place is more important than following strict proceedure.
If you are doing a hot, or Express application, you should boil and card immediately after application and be able to get a very shiny finish.
If you are doing a slow, cold rusting, the etch is happening in the box because it is rusting too long.
Hope you find this helpful. Some things are very difficult to teach via the written word, even with photos. I've been discussing rust bluing with some of the best for a couple of decades and my personal experience was always the most important, and last word.
