Would a ball park like South Side Park III (-3, -1, +1, 0,0) supress HRs as well as a ball park like Shea, Citi, or Yankee I? Do you think South Side would be a good choice in a 1970 progressive ? What style of team might be best suited to such a park?

pfattkatt, first I must say you stumped me on this one - I had to go look South Side up. Second, YOU are my guru on ballpark effects and how to build a team for the park, so I am not sure I should be giving you advice. 

But my impression is this, if I have understood the discussion that was around a couple weeks ago about park effect on the event tree: 

the home run effect of SSP should be similar to Yankee II or Candlestick, neutral, but then since it suppresses singles which IF I remember correctly, means that it plays a role in the hit/out part of the event tree, means that by cutting down on hits, it should proportionally mean fewer home runs inasmuch as these are a type of hit. But others will be more reliable on this point. 

Two dumb questions as long as you brought it up: does anyone seriously think that Yankee Stadium I did NOT favor home runs to Right Field ? Because if WIS is right about that, the Yankees apparently mistakenly built championship teams based on a faulty logic for 6 decades. Second, after having had the greatest home run hitter ever (fairly or not) why did the Giants then move in to a park that significantly reduces home runs as a factor ? It would be as if the Yankees after Ruth retired moved into Dodger Stadium. 

Actually, Yankee I did suppress HRs, even to RF, except for hitters like Maris and Berra, who hit 'em right down the line. Once you move over 30' or so, it gets very deep, very fast. And that waist high fence in LF and RF made for some spectacular catches that robbed hitters of HRs.
   But to the original question, I really am unsure what sort of team would thrive in a park like South Side. It would definitely help my pitching.