I happen to have the Shrew on hand as Dogodog included it along with the stock 8x11 dd that came with the Cibola as it was the Black edition. Of the 3 DD coils with delta connectors I have the 10x12 is the best and I use it for deeper hunting in open less trashy areas that have little iron.
When I have iron in the area then the only choice is a concentric. I have a 9" on the Multi Kruzer and 8x9 on the Tejon that I use the most. Keeping an eye out for another or an eliptical or smaller for the Cibola. Worst case scenario I will make a coil so size is on the table. A small 4-6 would be nice on the Cibola as it can be much lighter and better in trashy areas. Not worried about deep hunting as the tiny shrew on the Cibola seems to be ok at hitting a dime at 6" or so and it is a fixed ground balance machine so deep hunting is not in the cards on that machine.
I'm not a huge fan of mods people do to their machines. I like the stock look and layout of given machines.
If your looking for a light weight shaft system Steve Goss has an all carbon s-handle system. I may snag one for a machine I am trying to scratch build. Want to see if I can make an ultra light machine < 1.5 lbs.
I did a test showing the Tejon with 8x9 concentric using a silver dime and a trime under a piece of rusty can end. The can end is thin enough it only shows as ground phase reaction on an Orx and probably the same on the Deus. The Kruzer will give a boarderline iron sound. This is because the iron is so close to the ground phase that on any dd coil it will cancel all targets below. The concentric coil I am able to discriminate out the iron and still pick up the dime and a trime >6".
What most don't realize is that dd coils as good as they are in mineralized soil and target separation from their knife like detection field that they are more suseptable to masking. Even the tiniest pieces of rust can erase a target with them.