Yes, oil on the damper disk will increase dampening. Try a very oil and it might keep is more consistant. If your loose already to don't want it very thick.
If you were running on carpet I would suggest this for your problem. (1) Thinner t-bar, (2) .030 shim under front of t-bar, (3) thinner washer between rear of t-bar and pod plate (set your ride height of the chassis if you do this).
Keep doing those changes one at a time until you loose to much steering then go back a little.
take care
john