You don't really have to mount it closer, just use the flexi-arms and put the focus light where you want it. The picture below is the config I used last year in Oz. G9 with Canon housing, YS-27DX and same Nano focus light being discussed.
The flex arms are really handy.
After thinking about it for about a year, I have recently aquired a 2nd G9, an Ikelite housing with a short port, a DS51 strobe with TTL cord, a second slave strobe and alum arms. The rig is about 10 times the weight on land than the one I have. I'll let you know after my next trip if the pictures are any better. I already had the Inon wide & macro lenses, and am hoping to get utility of them with the new Ikelite setup.
PS, I really was touching dead coral.