About a week ago I made my first starter. I took some Arrowhead Mills
whole wheat flour and put it in a jar with some water (approx. 100%
hydration). The jar was placed in an oven with a pilot light, which has
a relatively consistant temperature of 90 deg. F. There were many
bubbles and a lot of activity after 12 hours, so I fed it again. After
one more feeding with whole wheat I switched it to King Arthur
All-Purpose flour, and moved it from the oven to a cabinet with a
temperature of 80 degrees.

It has been there now for several days, but it does not act quite as
active as I have been lead to believe it should from online tutorials.
It takes over 8 hours for the starter itself to double, and it never
seems to collapse into itself. It has many bubbles throughout and a
good froth on top, but even after 12 hours it will not collapse into
itself. Because it takes so long to rise and never seems to peak, I
switched the feedings from ever 12 hours to every 24, but this hasn't
made much of a difference in activity or odor.

At this point I am still keeping it at 100% hydration. Before feeding
it I throw out half (usually a cup, I keep it in a quart-sized jar half
filled up) and add flour and water until I have 2 cups again. The only
thing I've made with it so far are some muffins, which worked (I now
know there is some acid in the starter). I have been hesitant to try
and make bread, because with the slow rise times of the starter and the
lack of collapse/peak, I neither know when the best time to use the
starter is nor whether any bread I make with it will even rise in any
practical amount of time.

Why is this starter such a slow riser? Where is the peak and collapse?