The key to your starting 5, in my opinion, is getting both Harris and Lyle into the game together. Harris is our best point guard, but he needs guys around him who can take the ball to the hoop. Our two best guys in that regard are Lyle and Diop. In addition, Tate does most of his damage inside and Thompson is, right now, the better offensive option.
Unfortunately, Matta has an real problem because all of these guys are very young and inexperienced. So, no matter what lineup he starts, they need to learn how to maintain from start to finish and they have shown no ability to do that in any tough game this year. And, although Thompson and Giddens are going to be excellent, they are not excellent right now. Too many fouls! Too little offensive production. I would split PT between the two and also get Bell at lest 5 to 10 minutes every game.
The bottom line is that this team will go as far their defense takes them and they have to play strong defense through the whole game. So far, they have played great defense for about 50% of the game and poor uninspired defense the other 50%. So, the other team always makes a run and usually it is an early run and a late run, which are the worst possible runs of course.