Code:
Filename: "{src}\vcredist.msi"; Parameters: "/quiet";
probably that resolve one thing
for now i skip uninstaller section - it need more knowledge to do it proper [for example date isnt static ]
gameux see but dont know for what really is used
some games uses uninstall section to install patch
gameux looks easy to add [but probably need register dll]
edit something about GameUX for windows
game ux for windows on msdn
some progs to GUX
Game Definition File Editor