I was planning to start with a 10s3p which I will build in 5s3p blocks for easy balancing. That would give me 9.3Ah at 1.5kg.
My existing Konion packs are built that way and I have two 10s2p, 3Ah and one 10s4p, 6Ah packs I have been using for over three years with no BMS and no failed cells...