Four things to consider for next time:
- Sparge water may not have been hot enough or you may need a mashout (don't know if you did one). This was a problem with my first AG. The temp was in the low 150s at start of runoff and in the 140s at the end which is low. I sparge with 180 water now and the temp stays safely in the 160s without sweating over it.
- Crush the snot out of the grain.
- Use 5.2 stabilizer or add some calcium if your water is hard. I have never measured my mash pH I just use a tablespoon of 5.2 and open a beer instead of fussing.
- Be sure to drink plenty of beer during the mash.
If you do all of those things your efficiency should be consistent which is more important than being high. An extra half pound of grain is no big deal if you know you can count on hitting your OG each time. RDWHAHB.