In my experience the latency seems to be camera dependent. Some cameras I am using have a 10-15 second latency and other have a 5-10 second latency.
There may be a slight latency difference were the 10" may edge out the 8", but it may be only a second or two. Certainly not a dramatic improvement/difference.
I believe the latency has more to do with the limited processing power and H264 decoding capabilities of these devices. I see similar latencies when viewing my camera feeds from a Raspberry Pi.
Thanks, Robert