I have never worked on a Magnum engine. But I have worked on the 2.2, 2.0, and 2.4 motors that have TTY head bolts. They all have some type of initial target torque followed by a "plus 90 degree" tightening instruction. The second operation is where the bolt actually deforms and 'stretches' because the yield point of the bolt metal has been exceeded. Just like pulling on anything until it 'gives', the bolt has become permanently longer and thinner. If you re-use it, the part of the bolt that is going to stretch the second time is smaller than a new bolt and won't give you the design clamping force. I won't re-use them regardless of the check the FSM has. As to substituting conventional bolting, the whole purpose of TTY bolting is to get more uniform clamping force than you can with a simple torqued bolt. If the clamping force of conventional bolting is adequate, there is no reason you can't use them. But keep in mind the factory used them for a reason.