Sorry, will try to explain myself more clearly, I left out the underlying assumption that LdSH already has tanks.
2x tank regiments - LdSH and RCD
2x Mech Bn - 1 PPCLI and 2 RCR
in 2x 1+1 Regional regional groupings, 1 West, 1 East.
So the middle case, 4 actual maneuver units totaling 6 tank...