I generally go all strength. I also go with 2 hold block percent items. Then it is about choosing which two SAs I like best.
For run blockers I like first step as my extra SA. Since it is first in its row there is no need to use AEQ on it imo. I spend SP on that and it should cost 30 SP to take to 10. Then I like get low, cut block, and foundation.
That makes three SAs but only 2 AEQ items so a choice has to be made. Generally, I will go with a foundation and cut block item so then later I can spend my CEQ upgrades to take foundation to 10 without spending any SP in the pass blocking tree. I can take cut block to 3 with SP and get low to 9 with minimal SP investment.
That is just me. I strongly feel a pass blocking SA is needed even for a run blocker because he will most likely pass block at some point.