When I first started out, I had only the stock coil. It was very frustrating in trash areas, to the point I almost gave up on the whole thing.
The first coil I got was the 5.3, which improved things tremendously. I was finding AT LEAST 3 times the amount as before, along with the occasional silver or gold ring.
I did alot more reading on the various forums, and learned that a DD coil would allow me to run the gain wide open. I got the 6x10, and later the 3x6, and have used them exclusively for the last 2 years.
The last few weeks I got to thinking about the old 5.3. I came to the realization that wide open gain is not always the best policy, particularly if you are trying to sort out more than one item under your coil. I put the 5.3 back on, and I MUCH prefer it in general hunting applications. There is a better sound quality on coins, and it is easier to audiblly discriminate bottle caps and other iron. I can also more accurately determine the physical size of a detected object with this coil. (Ever dug out a squashed beer can at 6" looking for a quarter?)
I will still use the little DD for working small areas, or overgrown areas, at least until I try one of the small Excellerator coils out.
The DD coil has its place. I read some hunters thoroughly enjoy using them to dig little bits of non ferrous metal (small VDI number targets) out of a bed of iron laced sand. It is also excellent at finding tiny wads of tinfoil at 4" or more!
Seriously, I think your 9.5 will do well with the old relics, and I KNOW the 5.3 gets coins and jewelry in the trash. I have not tried the little Excell coil, but most that have say it does a better job than the Shooter coil I use.
I think I am at the point where I need to concentrate on learning more about the equipment I already have, and not chase the latest and greatest innovations. Then again, I have to spend all that clad on something...