2.5% is barely beer, is it? You might like to make sure your water is well stirred to even the temperature then add the grain and stir in well. You want the mash temp. to be as consistent across the grain as you can get it. If it ends up low you would need to use some of your sparge water volume as boiled water to up things, giving it yet another good stir in!
I habitually mash overnight. It saves all that waiting on brew day but brings in other problems. One is that it will often end up drier than expected. you can counter this by starting your mash much higher, like 68C. I also steep grains like crystal, which don't need to be mashed and add the liquor from this. This helps to prevent dryness as well.
I only do one batch sparge (of 6 litres). In my brief trial I found a second sparge made no difference to the results, others may have different experience, though. It may be worth posing the question in Brewing Discussions to see what people say.
I habitually mash overnight. It saves all that waiting on brew day but brings in other problems. One is that it will often end up drier than expected. you can counter this by starting your mash much higher, like 68C. I also steep grains like crystal, which don't need to be mashed and add the liquor from this. This helps to prevent dryness as well.
I only do one batch sparge (of 6 litres). In my brief trial I found a second sparge made no difference to the results, others may have different experience, though. It may be worth posing the question in Brewing Discussions to see what people say.