I do 1lbs batches for testing purposes only - testing new FO or recipe. I figure if it is going to be soap on a stick, rather 1 lbs of it than more. I have a scale going down to 1g so I can measure pretty accurately. Also, in the case of lye I round down, i.e. if it works out to be 64.6g of lye, I work it down to 64g. For water and oils I round up. As long as you stick to about 4 oils/butters in total it shouldn't be too hard. Just make sure you ran the smaller batch through a lye calc, don't just decrease the big recipe as you are working in small measurements. HTH