No you don't need to hold the remote button down. Press once to open then again to close shutter.
If you have it set in main menu to `mirror up`, you press to lift the mirror first....then again to open the shutter.
Have you got the `beep` set to ON? (might be useful when it's pitch black)
I struggled to even see the dial at night,
so bought a head torch.
There isn't a seconds counter, but it would be useful as you say.
I'm STILL trying different settings & getting to know my camera.
btw,He who dies with the most toys, WINS!Nikon D800E & D700 bodies + Nikon 200-400mm F4 VR1, 50mm F1.4G, 16-35mm f/4G VR, 105 F2.8 VR macro, 70-300mm lenses. A couple of filters, Giotto tripod & ballhead. Lowepro Slingshot 302 AW