Hint for getting best ending: 1) If you're manually forwarding time you're doing something wrong. 2) With the wizards, it's about getting the slowest pair to cross together. 3) Do the second job late.
Great strategy: Use remote detonation charges, wait until the enemy (preferably those pesky grenadiers) is right next to a wall, place the charge and set it off immediately. Your own explosions don't hurt you, but the guy on the other side of the wall will never see you coming. Which means he wont hit you in the head with three grenades.
I happened to try and put the new fuse in place without removing the broken one first. The new fuse just disapeared from my inventory and I cant get a new one. Fuse still broken.
Disconnecting should mean ordinary loss. Otherwise you're going to get the same problem as always in games like these: People disconnect willfully when they're about to lose.