Thanks Chris. Ideally I'd like longer subs, but the current camera (the G3) mandates drizzling, and this in turn needs a LOT of subs to work effectively in increasing the pixel resolution. So it's a bit of a trade off. With a higer-rez camera, I would definitely be aiming for 30 min subs. Here I went for 10 min, but I think in the future with the camera I'll use 15-20 min subs as a compromise
Oh, and I do plan on getting a more advanced camera in the not-too-distant future!