The fact that the BU credits eclipse the rest of the projects has no bearing on the rewards!!! Gridcoin accounts for the difference, BU miners get the same share of the daily mint as the rest of the 34 whitelisted Boinc projects by Gridcoin.
Thanks for the explanation. Is there a decent info-graphic that shows how this works? I think it would really help bring the complexity down to earth for the "casual cruncher".
It is rather easy: Each day each project gets ~1470 Gridcoins paid out to it's researchers/miners.
How much coins you get for a single project depends on your percentage of the whole RAC in this project in team Gridcoin.
What you earn in total is the sum over all projects.
Because of this projects that give out RAC easier do not have any advantage over other projects.
I also agree with Scaletrix, the Gridcoin community is great, it's only very underrepresented here on bitcointalk, as the main forum is somewhere else:
https://cryptocointalk.com/forum/464-gridcoin-grc/