Advices accepted on best workflow Premiere-After Effects

Hello,

I have been using Premiere and After Effects all my life, but I know I don't use them as I should. Until now I finally understood how those two programs can be utilized at the same time (I was the kind of guy who decided at the beginning of a task if the video was simple enough for Premiere only or heavy-animation loaded for After Effects only)

My current workflow:

I am editing a "motivational" video on Premiere with video clips and still images, whenever the stills appear they have a duration of 10 frames each and I put around 10 to 15 of them together. To add this pictures, I create a matte solid in my Premiere sequence which I then replace with an After Effects Composition.

In AE I proceeded to import all the images to the linked composition, limit their duration and position in a sequence, etc. Then I go to Premiere, prerender the sequence and see if the frames go along the video, if not, I go back to AE and remove some of them, or add others, etc. Then I go back to Premiere, restore unrendered and prerender again, continue with the video and the process repeats several times. (Reason I want to process the image sequence in AE is to take advantage of frame blending and other features)

Is this the best workflow for what I am trying to accomplish? I am wasting a lot of time going back to Premiere and prerendering those compositions; otherwise, there is no way Premiere plays them without freezing the image every second, this is the first time I am using these dynamic link capabilities, I even used Audition to remove some noise of an imported clip! I feel like a pro, but I'm far from it.

Any advice is appreciated, am I using the programs upside down? Another thing, when I prerender, I choose the lowest quality as I just want to know how the sequence flows in time, do you know which video format would render quicker for these often "Render and Replace" tasks? Thank you!