Another view, FWIW:
When the blades are immerse you should have automatic stability, since
they & the oarshafts displace water & thus generate righting moments in
proportion to their depth of immersion.
If you drive with unbalanced foot pressure then every other part of your
body will be trying to compensate for the eccentric loading, which may
result in unbalanced blade-work, but the feet should not need to be
balancing the boat during the stroke, only not un-balancing it
During recovery you should have no water contact, so this is where
stability can be disturbed, but here you have no foot pressure in the
accepted sense. So you need to ensure that the load is evenly
distributed on the seat as your new prime point of contact with the boat.
Some of us can never balance a 1x, often because our butts are lopsided,
so the seat loading can't help but be off-centre. Rectifying that
demands adjustment of the seat - raising one side (or that side's track)
by 1 or a few millimetres - which can be most effective but which I
never hear discussed.
Rowing's a simple sport, & understanding it's problems is often simpler
than we like to pretend, so why are simple concepts like this never
discussed?