RE: 6s lipos on Astro model 210 brushed speed controller.
Thanks Greg, Astroflight finally got back to me & stated the speed controllers could handle the slightly higher voltage.
As for the cut off voltage I plan to just time the flights VERY conservatively & land at about half of the battery's capacity.
This will still give me an easy 10 minutes flight duration with the bonus of only 1/2 an hour to recharge back to full. - John.