How many autoblog posts per day?

Does anyone have a recommended maximum number of autoblog posts per day? Are there any risks with having a lot?

No one could give you accurate number.
The most safest way is to start posting only few posts a day, 1 - 3 post a day, then increase over time. I wouldn't go more than 10 posts a day which is too much IMO.

Many that used to post 100+ posts a day got their sites deindexed and marked as spam so be careful what you do, and try to randomize post time, don't update your blog everyday in the same time.

Growth of posts should look natural. If you plan to post alot of posts daily it could lower the chance to get banned if you turned off the ping option when posting a new post.