I don't think I've ever talked to anyone who understands emulsion jetting. Everyone just guesses at it. Nobody seems to know why Holley switched from 2 emulsion jets to 4 or 5. Maybe Braswell understands emulsion. At least he claims to but he never explains it so even he might not know.

Having said that, if you copy an old 850 DP you should be fine. Put an 028 in the top hole, blank in second, 028 in third and blank in the bottom. That should work well enough to get you going. You can play around with it if you want but I doubt you'll tell any difference. I've tried a bunch of different emulsion combinations over the years and never really noticed any difference.

If you really want to talk about emulsion jets then Tuner is probably the one guy on the internet who knows his stuff.