I would use two more if you're set on using lead and your controller will handle it. Sag is HORRIBLE! Mine will sag to 30% or so on hard accell.
You can get lithium 200ah which triples the mileage at half the weight for about 12500 Calb. Mine will be delivered the 21st.the main resin for lead is $3000 or $20000 for lithium next change maybe