but neither of these titles add to the JSA continuity. SMT is not even in the same universe.
I agree though that it's excellent but in my experience knowing the JSA ads to SMT because they sort of pop up in a story (haven't read all because of the state of the collected editions) but SMT doesn't inform any of the JSA titles.
Starman kinda intersects but other than Jack Knight doing stuff with the JSA it's not important to read Starman to enjoy or understand JSA.
And good luck collecting both of these....