I like the idea of the color scheme slowly changing as the sun sets but things get a little surreal with the reds in the middle of the comic. Also, I'm wondering what you are going to do with the past tense thoughts, it kind of takes the reader away from the moment to moment unfolding of them. Although I think it turned out well in "A New Fit" with the ending.
Past tense narration is just a story telling convention, it doesn't mean that someone is actually telling the story. The New Fit ending was a joke on the convention. I don't think this: http://sexylosers.com/201.html sort of ending would be a good idea here.
I picked past tense narration because it made the most sense for the transformation scene. It's hard to get believable present tense thoughts from a character who is having some intense unknown experience. It would either end up realistic and not contributing to the story, ie "what the fuck is happening!" over and over again; or it would be implausibly level headed ie "hmm I appear to be losing consciousness".
On this page, I found that past tense allowed for some interesting ways to describe things. For example, if you convert the second paragraph to present tense it just doesn't work. Past tense makes the introspection a more believable.
Going forward, the past tense narration can be used to convey embarrassment and post-act rationalization. The thoughts can say "it's not like I wanted to" but the action can clearly indicate that she did.
oh to have her cute lil body... very well proportioned... it is exactly what i would wish for... the full body drawing on the left has PERFECT proportions, the waist/butt/legs is something she should be very proud to show off. also love you made have extra large breasts too. i wish she would embrace this new body sooner than later but have a feeling Mistress will have to drag her kicking and screaming towards that goal, LOL.