Neal,
Welcome.
I'm in your division, so I'll forego discussing your team in any detail.
Ballparks do matter. BPHRs are explained to some degree on the "how to read a stratomatic card" link on each of your player's individual cards.
In general, in a park like yours (Griffith), you can afford to carry pitchers that have BPHRs on their cards, because Griffith will negate them.
Conversely, as a general rule, you don't want hitters that depend too much on BPHRs, because they won't get those at home. That's why Flood may work better for you than Thomas. Pitchers like Boyd, Wilson and Drysdale are often seen on Griffith teams on a budget.
Here's a handy tool that may help you; you can click on the "ballpark effects" link to get an estimate on how each park affects a given player:
http://www.diamonddope.com/card_reader.cfm?tab=cardread
In case you did not know, each of the individual player cards have settings you can fine tune to hopefully make the game engine heed your wishes. Be sure you set those & your manager strategy before we start playing tomorrow.
If you have any questions, zip me an intraleague message.
Randy (JUMA)