Hi Malcolm

All my 5300's when prepared as 10s (one + and one - lead on each pack made shorter and soldered together) and using the Hobbycity 4mm red jacket connectors weigh between 1180g and 1190g ready to fly.

I have not used the 5000's, but have seen some numbers and they appear to hold a little more voltage than the 5300's but the 5300's are still stronger than anything we have had in the past, so either way its great power I have chosen to continue using the 5300's as I feel that there is greater pack stability and resistance to abuse of a 2P configuration vs. a 1P configuration, but that is simply my own preference. I think you would be fine with either.