First, I've got a fairly bog-standard red/green science setup I came up with (borrowed from a few places, but mostly my own design, even if it's not terribly creative) that I wouldn't mind critique on. With only minor tweaks, it's pretty well infinitely expandable, and it's a fairly compact build for 5 red/6 green assemblers.

My only "issue" with this setup is the gear assembler on the green pack line doesn't quite keep up with the inserter and belt assemblers. It's not terrible, especially once I upgraded the gear assembler to the blue, but the inserter assembler has a brief moment of downtime every 2-3 cycles. I put a small buffer chest on the belt assembler, limited to one or two stacks, both for personal use and to get the belts to ride on the north side of the output belt. I'm using 5 red and 6 green assemblers to try to give me approximately one of each per second (5 second construction time for red, 6 for green).
This setup seems to feed 10 labs fairly easily. I haven't noticed any shortfalls when the labs are running full out. My question, though, is how many labs would this support? How many labs should I need by mid/late game? I've gotten blue science automated in another world (that I'm abandoning, due to poor base design choices on initial set-up) but I'm not sure how many science assemblers I should put up for each level of science pack.
Thanks in advance for any tips/tricks/advice/feedback anyone cares to give.