Well, I've neve been west of Chicago on the mainland of the good ol' USA. But Lewis and Clark Lake held the TBF divisonal a few years ago, and they may have some info on the TBF web site about it still. This is where you as a younger angler have a lot of advantages. Most of us didn't have the luxury of the internet to look up info on lakes.
I wish I could give you more specifics about the lake, but I can't. Fishing for smallmouth IMO is all about determining the forage and finding the fish (seasonal pattern). Believe it or not, but June 29th in SD will probably be post spawn fishing. All the fish would probably be done spawning. I was just in northern MIchigan and the first fish were just going to the beds. Water temp was 64 to start the day.
Tubes, spider grubs, small jigs and spinnerbaits, and craw and shad pattern cranks are good places to start. Good luck in your tourney.