jss,

both of those rifles are optimised to use standard 144gn NATO-spec 7.62mm ammo. There is not much point in using any other load (Envoys are just as accurate with NATO surplus as they are with 155gn and 160 gn special match ammunition).

"I would like to keep the pressures to a minimum especially in the Savage as the bolt head is at No2"

You may be under some misconception here: there is no known issue with 7.62mm No4 conversions and any type of 7.62mm or .308W load. The bolthead size is irrelevant; that was just the size used to achieve the headspace with that particular barrel - the receivers do not increase in headspace (ie stretch) under any measurable or known circumstances. Many 7.62mm target rifles have shot thousands of rounds, yet retain their original headspace.