Hi C.J.M., I think you made a smooth move by getting the 5X10 for your T and I would especially suggest getting a 5.75 Con. for it soon as you are able. As for overall, the standard 9X8 is likely the agreed "deeper" coil, with the 5.75 only a hair or so behind, and then the 5x10. Be sure though that they all are separate and exceptional in doing their "particular " jobs. You will find a special place for using them all and being glad for having them. 5X10 is best overall for coverage and depth, 5.75 great depth also and the really iron trash littered places and the 5 X10 gives you a more narrow search pattern if you wish, in those same iron trash sites and it also better hunts any mineralized/ iron trashy you may have. I found a really rare early( Andy Jackson Troops) button at about 5" at an Iron mineralized site that I and several others had pounded already with Tejon , 9x8 and 5.75., Cibola 9X8 and a Whites. Do some searches here on the forum and some past comments should show up on the 5X10 ws. HH Charlie