As far as I know and what I have read on numerous topics, #7 does not contain any solvents or abrasives. It should be a pure polish/glaze. And I read somewhere that it is perfectly ok to put a layer of #7 on top of the wax layer for a really wet looking show-shine. It wont last many days without any protective layer but it should not eat up your wax layer either.
I don't even think you'll need to top it off with a wax layer if the layer beneath #7 is in "good condition".
I think it could be a good idea to try out, but I am a newbie when it comes to detailing so don't read my words like the law.
I'll try to find a link to the article about topping with #7...
regards,
silli
Edit:
Yup, found it, it is in this thread:
#7 By Mike Phillips
"However… right before a show… to make the paint look wet and to fill in hairline scratches, it is perfectly aright to apply the #7 on top of the wax, thus the name… Show Car Glaze."
hope this helps.
Silli