Thanks.
The 1/4 cup per 5 gals (4 gals) is appropriate. We found that higher concentrations didn't help.
We've visually tested many times for trichomes and found no significant loss. We also tested for final THC% and found no significant difference. In fact, one batch of tests showed
higher THC in the washed bud.
No worries about *gasp* dunking your harvest in water and vigorously swishing it around.
One thing that I want to offer is my reluctance to separate the lemon and soda buckets. That doesn't sound like a good idea. They should be mixed first into just one bucket. Juice first, then soda, mix it up, dunk your buds.
[Edit] I also don't believe that any foaming action has much benefit. Any foaming is gone in seconds. We're not trying to remove anything with kinetic action. It works on a much smaller scale, loosening water soluble bonds. The dunking and swishing itself removes as many stuck insects as any foaming would.