Bill,
I only used the Advantage for a short period of time as it just didnt work out for me and my coin hunting, but will say the GT mounted under the arm rest works great and feel it will help on the weight problem.
The Sovereign has to go slower as you are hearing much more than you ever did with the XLT or the Musky, if you go too fast depth will suffer as you will probably not even hear the good targets close to trash. I find the slower you go and the more you listen for those tone changes the deeper your finds will be. Now you only want to go super slow where you know targets will be 8 inches and deeper. I went as deep as 14 inches and the display of coins I posted from Oak grove park you see down a little on my post to Art were from 10-12 inches deep and if I would not have been swinging the coil very slow I would have missed them.
As far as separation i feel the Sovereign are excellent for that and with the tones you will hear different targets close to one another where many other detector will average the signals of the target.
As far as meters are conserned I like and use the SunRay meters, but they are no longer made, so you have to find a used one if you want one. The Minelabs meters that were rescaled to the 180 number too were good, but now this new GT if you oder a new meter will be a 180 numbers and now only works with the GT while the SunRay works with all the Sovereigns. The Patriot meter I had and used it a few times and sold it as it was not as percise as the other meters were. The digital I could tell number differnce by one number while with the Patriot I found I could not do this. I also found the 180 meter are faster to respond, but the Patriot you dont have to learn what number means what as it would say it on the meter. With the SunRay or the Minelab 180 meters I found my good coin like copper, sliver and clad would read 179-180, the IH and new zinc pennies and some of the older wheaties would read 176-177 while the screwcaps would be 177-178 in most cases. The nickles would be 144-145 while the beaver tails off the round pulltabw would be 140-141 and yet the war nickle could read from 143-151, but you knew it had the tone of a nickle. With the Patriot I found I could not do this as there is no digital display and it was hard to tell the close one like I could with the SunRay or the Minelab 180 meter.
As you see many like the Patriot meter and do well with it,but it was not for me and my hunting.
Main thing with any one of the Sovereign is it will take time to understand this detector as it is differnt,but once you do I am sure you will love it.
Rick