Thanks DeathAndTaxes

This is obviously in exercise guessing optimisation depending on variable use cases.  My fear is that that adoption will be held back and hence the rate of network propagation will not be an issue for a very long time.  I suspect even 2.5 minute confirmations would help (not litecoin obviously) for only an 8% decline in security where the hash rate seems to increase by more than that on a month by month basis.

Out of curiosity what constitutes a fully “propagate” message what does 12s quoted above relate to and is this likely to be subject to infrastructural improvements if block sizes rise substantially.  I believe processors like Bitpay “listen” to specific nodes for near instant confirmation to mitigate double spend risk.