I thought exposure was more to do with anxiety level and your ability to tolerate it. Therefore it matters not how long you can stay at a low level as long as at some point you reach a point where it noticably bothers you. This can vary day to day depending on a number of factors. Amount of sleep. Coffee. suroundings.
The object is to teach yourself to tollerate what ever you are exposing to with the object of having it eventually not trigger anxiety. Mostly by using relaxation and coping skills and "I did it's". Slowly working up to exposures with a higher anxiety level. Therefore the number in a day would not matter as long as they call for some action on your part. Don't rule out ones of low level, they still contribute to the overall picture.
The object is to be able to do something you should normally be able to do, not the impossible.
When people have a number of exposures to do in a day they do them in two different ways. Some want to get the tougher one done first so the rest are tollerable. (jumping off the deep end) others want to work up to the tough one with a lot of "I did its". No one way is right for everyone.
The amount of time sounds reasonable. As long as the fear rating is not too high and you gradually work your way up to more anxiety provoking activities then your plan sounds good.
One of my treatment goals is to expose myself to stressful situations. I have a lot of stress when I have many things to do at one time and especially if involves going from one place to another.
In this way I developed a exposure plan to do several activities in one day with each activity in a different place. I am starting and ending with 3 and 8 activities respectively. The problem is that to do these activities, and because it involves commuting from one place to another, it takes me 2 or more hours to complete the experiment.
I would like to know if the experiment could be effective for so much time or I need to find activities that are less than one hour?