I believe that when permits are highly limited, the 8 and 10 am lotteries may be the only choice. I've done that twice. If there are a lot of extras (e.g October, June), they will free them up earlier in the week for walk ins. I did that once. But it occurs to me that this year may be different b/c of the new relationship with recreation.gov, which is why folks may want to call the interagency office for updated info.
