Most landings runway length is not critical so brakes are not used until around 80 knots to save on brake wear on my airline. I used the same technique prior to the airlines also.
From reverser deployment to 80 knots small rudder inputs are used to maintain centerline tracking. Crosswinds and assymetrical thrust application would be the main reasons for correction to remain on centerline. This is the time to see the results of a bit of assymetrical thrust to maintain centerline using rudders if necessary to maintain centerline tracking. It will soon become easy and instrinctive so one day when things go south you have that extra tool to bail you out of a situation.
You haven't broken any rules because no pilot can keep perfectly balanced reverse power anyway when most of your attention is directed out the front window.
Obviously it wasn't in this crash causing it from the start.