I second the carbon fiber straight shaft, I use an Anderson.
I also find a harness helps if hunting the wet or dry. I use the Minelab ProSwing but you can use any bungee harness, it helps with the weight a bit, as its a heavy detector......because its multi frequency VLF and waterproof, requires a bit more material.
The discrimination is nice, but try not to use it at first. Put it to "1" rather, and dig everything, it will take a few months, as with any detector, to learn the tones. When I have hunted trashy areas, the scrim really helped, I was impressed. You can't notch anything, but it works quite well.
I recommend a knob guard, it WILL fall over, and when it does, you don't want to have to send it in, its a cheap investment that will pay for itself!
Hose it off throughly after ever use with fresh water!!
Don't crank on the knobs, slow even pressure. If you torq to hard on the knobs, or go past their limit, they have been known to break, which may require sending the unit in.
You made a good choice with the Excal!
