The first idea isn't an issue, at least IMTU and - I think - in canon. The winner of a third blood duel doesn't get anything special (certainly NOT his opponent's lands and title), except possibly a warrant issued in his name for murder.

The second idea is reasonable.

But why the requirement that the challenged person use a champion? But the challenger can't? A duel that is a matter of personal honor is cheapened by allowance for champions (paid thugs). The only time I've used champions IMTU is when the opposing side has demonstrated itself to be without honor . . . in which case, in addition to the actual champion, I threw in a team of snipers with laser sights to make it clear to the player of the PC in question that he had to fight this duel if he wanted ANY chance of leaving the field of honor alive.

For almost a year of game time, this player had been dodging an Aslan High Noble whom he had severely insulted. Strangely, said player showed zero interest in the hatbox-sized stainless steel container which the champion's second was lugging about. This turned out to be a portable low-berth . . . into which the PC's head was placed (for sending by courier to the High Noble) after the champion won the duel.

The player in question declined to create a new PC and left the game, for which the rest of us were grateful. He had been extremely disruptive. We all wanted to play, he just wanted to grandstand.