In the AIB thread in the Newbies section it was weighted at ten points, which in the grand scheme of things, is next to nothing. However, each and every point counts, it is based on your score compared to what the Institute of Naval Medicine believe someone of your age group should attain.
Or so I was told at AIB, I think that 10 is the minimum you should get, but just because you get there don't stop, every point counts! I didn't get there, to my shame, but still passed the overall AIB.
When I did AIB last month I was with a board of all RNR.
Bleep test counts for 10 out of 300 points. It's a test of determination as much as it is of stamina according to my ACLO and the briefing we had there. Keep running till you throw up - if you dont throw up afterwards you could have probably tried harder.
The only difference from RN applicants appeared to be that the Naval Knowledge Test will differ if you are RNR DE candidate or current RNR rating going UY/SUY route - DE candidates get same test as external RN applicants, UY/SUY Ratings get an in service (more difficult) set of questions.