I would tie a few with the hooks spaced just like you would for a regular harness and a few with the last hook about 1/2 that distance try them and see which you prefer. But like stated earlier the closer you can keep that first hook to the spoon the better. So as for length that would be depends as you would not want it to long but it has to be long enough so you can attach the snell to the spoons split ring and then cut off that tag end. As you can see ebijack has attached his with a crimp on connector directly to the split ring. If you use his picture as a reference you cannot go wrong. Attaching the snell this way keeps that first hook close to spoon, I find it to hard to tie it close to the split ring so I also use a crimp. So far none have failed and you can carry extra snells, crimps and crimping tool and change them on the water while fishing without to much difficulty.