This was not found by myself but I didn't see it posted here so I thought I'd share it.
If you pull the 2nd boss of SFK to the instance portal and kill all the adds he spawns then zone out before you kill him the guild xp stacks from it. So you zone back in, repeat the process and eventually when you kill him you will get spammed with guild rep/xp.
Since I am in a very small guild trying to cap the xp every day was a huge pain and we had to chain run heroics which was burning us out very fast. This method is boring but it only takes about 30 minutes and will cap the xp easily. Depending on if we got the aoe adds or not we would generally reset him about 7-8 times for the daily cap. I believe that each reset adds about 15% of the daily cap though. Of course once you hit lvl 23 and the cap is removed you can just do this a bunch of times to hit 25 which I think some people must have done considering how fast they got it after the cap reset.