Kristina, I love how these are coming along; they are super unique and elegant. I did enlarge the RSVP heading, but I personally think you should stick with Please Respond, simply to keep font size uniformity between both enclosure cards. The RSVP is large now, but Details, can't be any bigger because of the amount of succeeding text. Let me know if you want to change it back to please respond, or if you'd like to keep it as show. I did rearrange, and edit the details card, by adding for additional details, above the website. I also added the attire info. Additionally, the font has been changed to a more striking script/calligraphy. I would have loved to go more "wispy," with the letters, but as you mentioned, I don't want it to become overcrowded.
Finally, I would suggest going with the ivory enclosure cards, rather than changing the foil color to maroon. I have had other brides do 2 different color cards, and it still looks very beautiful. As long as everything is still within the same color scheme, it shouldn't be a problem + I like the contrast. With the ribbon and extra maroon rsvp envelope it should all come together once packaged.