This is a fairly comprehensive sleepy advice:
. I assume it's probably optimal to meditate when well-rested,
Not necessarily, if I remember correctly, Ven. Yuttadhammo even mentioned that sleepiness can be a great meditation object.
- Yes, in my experience, and to a certain extent, they go away with gaining meditation experience
- Scheduling is not that important (in terms of when to meditate), but if you find that most of the time you are sleepy, that will slow down your progress, so try to schedule some times when you are less sleepy aswell
- For me, alternating walking and sitting meditation is often easy and helpful, and when I'm sleepy, I reduce the duration, so I may be meditating in 5 minutes batches - walk 5 - sit 5 - walk 5 - sit 5 - walk 5 - sit 5 (and often, after the first 5x4 = 20 minutes, I can meditate longer without being sleepy)
- Doing only walking can be an alternative
- I would avoid stimulants, especially regularly, they mess up with your metabolism and you may end up exhausting your body.
- try to find a balance in your daily schedule so that you are properly taking care of your body and allowing it to rest
Finally, there are many methods, and sometimes, one method will work better, other times, another method will help.