I don't know about a second strap, what if you end up in a nasty situation were you have to get rid of your helmet? A second strap does not only mean more security when it is supposed to stay on your head, but it also means more time when it is supposed to come off your head ;)
It's your own call of course, but I think the chincup should do the trick, in combination with a quick release.
I jump an Optik with a top mounted video and front mounted stills. I like the helmet. Its light and comfy. I have the video in a bonehead D-box which I highly recomend for ease of mounting and giving the camera some protection. The chin cup is plenty. You do not need to add a second strap. Too much to do if you ever have to ditch the helmet.
what if you end up in a nasty situation were you have to get rid of your helmet? A second strap does not only mean more security when it is supposed to stay on your head, but it also means more time when it is supposed to come off your head ;)
I have an optic with the articulated ringsight and I found that I don't need to use it, I can get the helmet on and off easily without moving the site. I like to move it out of the way when I'm under canopy and for landing so I like having the swivel.
On about my tenth jump with the optic I had a really hard opening and the whole thing nearly came off my head, I just caught it in time. I called bonehead and got a chin strap and cutaway system (about $32 for both). I mounted both the chin strap and cup so that they will both cutaway when I pull the loop. I have the chin strap sorta loose, it's just there as a back up. I pull the cutaway every couple of weeks (on the ground ) just to make sure nothing has changed, like a bent cotter pin or something wierd.
No worries, I was in a hurry to have it jumpable within a day so this was my best option. Also, I had the cutaway system built myself for a couple of dollars but when I saw the loop (that you actually pull to cutaway) I really liked it. It stays put where I want it and is easily accessible. At the time it I was happy to pay some $ for peace of mind.
My optic has worked well. i like it but it doesn't fit my head very well, but that's my fault for having a wierd head. i have to buckle down the chin cup to where it's really uncomfortably tight. no fear of it coming off, ever... but i'm glad i went to the flattop narrow.