I think 10 hours of sleep might be a little more than just a "good nightly rest". I use the rule of getting up at the same time every morning and only going to bed when I'm sleepy. I figure my body will tell me when I need to sleep.

I did most of my riding this Summer on weeknights. I think as long as it doesn't affect your sleeping negatively it should work just fine. I mean, I've seen lots of sources that say getting your exercise in first thing in the morning is best, but I figure that if you think you can get a better quality workout during the evening then to go for it. Whatever works for you!

One of my friends actually found he rested BETTER if he went for a hard run right before bed. He had some insomnia issues, but if he went out and beat himself out he had far less trouble sleeping.