You assume that moment would be televised. I'll wager that the damaging information will be unclassified, while the exculpatory testimoney will be labeled "classified" and as such will be given during closed-door sessions. The GOP has no power. They don't control the hearing procedures in the House nor the Senate.
You raise good points. I do think that the Democrats overestimate the public’s acceptance of their view—and will want to try to publicly humiliate Bush. They had control of both houses in 1987 yet still thought public hearings were the way to go, then North basically blew them away.
We shall see of course . . .