Hi Pet.
Like Eric said, I use and love the 5x10 on my 1500. To date, it's the best detector coil combination that I've used. (had a yarn with Snowy on the phone a couple of hours ago, and he said that you do pretty good with your GTI.) The reason I like this coil is twofold. One is the terrific target separation you get with it. The imaging coil doesn't get close. The second reason, is the ability to tell our coins apart from other targets. $2 coins give half a tone when you whip the coil over it (after finding it at normal sweep speed) $1 coins give 3 quarters of a tone while screw caps always give a full tone, even when they are squashed! 50c pieces also give a full tone, yet a full silver florin gives 3 quarters of a tone. Pennies (these are the same as large cents for you US readers) give a full tone. I can't remember about 1 and 2 cent pieces, but assume that they wouldn't give a full tone.
The target separation with the 5x10 really came into it's own on New Years day last year. I took the 1500 armed with the 5x10 down to 3 parks on Sydney harbour foreshore. Got there at 6AM and went to 5:30 PM. There were many thousands of party gores in these parks, watching the fireworks display drinking and generally spending the whole night having a good time. As I arrived at this park, literally around 30% was covered in pure rubbish, up to my knees in height at many places, and you can imagine how many crown cap are in these parks as a result of these same parties going on for who knows how many years! There were times that that I could only use the coil to push the rubbish out of the way, due to the rubbish being so thick. The council workers did an amazing job of cleaning this up. It was clean before lunch! Despite hitting ridiculous amounts of crown caps, I rarely got fooled by them, even though at times, they were coming in at the same notches as our goldies. Coins gave a better cleaner signal. Set my personal record that day with $118 and a case of dehydration! (ran out of water and there were no taps etc.)
I've only ever used the Garrett 4.5 coil on the Ace I haven't hunted with it in open areas much so can't tell you much about that. Where it was really hot, was around play equipment. It's a coaxial coil (double shielded) which means, that when in pinpoint, it literally has NO signal above the coil, or to it's sides. I've found a $2 coin in real world conditions directly under metal frame work that literally went down to the level of the bark chips, and the coil WAS IN DIRECT contact with the metal above! You need to tilt the coil away when searching next to upright metal parts (holding the pinpoint button in of course). The downside is, there is no discrimination on the Ace when you do this. I don't know how it goes with the GTI, but I think that the discrimination still work when pinpointing on them.
The 5in DD coil sounds interesting.Don't know anything about it though. Looking forward to seeing how the DD coil works on the Ace. If it behaves like the 5x10 on the GTI, I'll be very impressed indeed., but that's another story.
Mick Evans.
I like the Sniper too, it will pick rings out of trash for me...but I have had better luck with my stock coil for silver coins.
.Happy Hunting!