Thanks Bill.
I was using a 1/2″ Watec 902 Supreme up to recently but in the past few weeks have upgraded to the 910HX and the increase in sensitivity is noticeable. Noticeable increase in the number of meteors for which I have recorded a spectrum.
I am also using a simple 500L/mm grating from eBay and a 6mm f0.75 lens – nice and fast yet with good optical quality.