Most modern autobrake systems will deliver a programmed rate of retardation.
What do I mean by this?
Well, you select an autobrake setting 1/2/3/4/max (min/med if A320) and this will deliver a rate of deceleration off x kts/sec etc.
You choose a setting to deliver the performance you require based on an approach (ground)speed, lets say for example 150 kts and A/B 2 will stop you in 2300 metres for your planned exit point.
The reverse helps here, but the programmed decel rate remains the same, so reverse reduces the amount of braking effort of the autobrake system.
I'm sure that all airlines will select at least idle reverse (at least momentarily) and will use up to full reverse if required, although many airports stipulate the use of minimum reverse idle commensurate with aircraft safety. The selection of reverse idle will result in modern high-bypass engines in very little noise at all.