Simple answer... Don't
Safety fuse is not very safe. It can burn underwater, so it has an coating that encourages the burning fuse to stay lit underwater. When used outside of water, it creates a slag that remains hot up to minute!!! I have ignited match heads and other fuses just by touching the slag of a burnt fuse. This slag is hot enough to catch grass on fire!!! I even seen this happen when the grass is wet.
Using a fuse with a model rocket is a bad idea for several reasons.
1.) Motor ignites, and throws slag a good distance away from model, landing only God knows where. It could land in the bushes, grass... on your shirt!!! BIG FIRE HAZZARD... and the fire can start a hour after you left the field.
2.) Pad could collaps with the rocket pointed towards you. I HAVE SEEN THIS HAPPEN during a 5 sec countdown. If a fues was used, there would of been no way to abort the launch.
3.) If the fuse does not light the motor... the slag can... You light the fuse... nothin... wait a few seconds... aproach the rocket....SWOOOSH!!! Not safe.
Get a simple Quest 9vt launch controller, a launch rod, and a coffee can. That is all you need if you just want to launch one model.