First thing is to print a Stouffer and see if you get fog on that. I think your decision to cut back on exposure was a good one and I suspect you will end up finding the correct time to be something close to the first time you cut it in half or maybe a bit less. If you do get fog on the Stouffer, you will have to figure out if it is from exposure or some sort of chemical fog. A Stouffer 21-step has a density range of 3.05 which should be more than enough for salt printing.
Second, print one of the collodion negs that you like the sun-exposed print of using the EEP box. Try to match the shadow rendering to determine the correct exposure. (This time will not be relevant for digital negs.) This will give you a direct comparison of the difference in how the 2 light sources print. It could be significant, but maybe not. Either way it’s a good thing to know.
Third, if chemical fog can be ruled out, and you nail down the proper exposure time, the next thing will likely be to print the Limiter target and make any adjustment that might be needed there.
PS - What’s your name?