Kent,
I have not used an Edge, but I have a CZ6a.
For the CW site, I would hunt using either the stock 8 inch coil or the 10.5 inch coil in all metal, and dig all targets that are mid to deep. I would check in discrim mode and size them up in pin point and dig the deeper, smaller foot print targets. I would also make a note of where are the patches/areas of nails and iron. Once they are found, I would switch to the 5 inch coil, up the sensitivity to where it's on the edge, sweep very slow and sniff out the deep buttons and targets that ID above iron, and ANY target that is IDing as anything, including iron, that is deep.
For the trashy home site, I would use the 5 inch coil and do the same type of hunting. I am not sure if the Edge is better in trashy areas than the 6a, but I do know this. I picked up al like new used Coinstrike ( thanks Richard from Backwoods) and after only 2 hunts, like this machine a lot. I hunted a trashy ball field twice with this machine, and have found deep copper pennies, a few wheat backs ( no silver yet ) and only 1 ( yes ONE ) iron target...a rusty nail. I did dig a lot of foil and aluminum, but I have to because I have found a few gold rings there. But, for the last hour of each hunt, I strickly coin hunted and only dug targets that locked on in the upper ranges, and did not dig any foil or aluminum, but did dig a DEEP penny and 2 very deep brass items.
I think the Coinstrike is a great value now...there are a few new ones with the 5 year warranty for about $500...and the used ones are running about $350-$360. I think in reading all the great tips for the Coinstrike, the main one to learn is sweep the target at ALL angles and if you get a good lock on ID without any negative numbers jumping in...DIG IT.
You won't find many, if any, used in good condition 6a's ( at least you won't find mine for sale), but if you do...GET ONE !
JC