First, I remember back to when I just started and I had many of the same questions - hang in there - your last FS was better than the first and they will continue to get better as long as you keep and open mind to suggestions.
The issue of cat will be one regardless of sponsor and has less (or nothing) to to with the sponsor but with the the content you use on the free-site. My pay site is a teen/amateur pay site but I submit FS's to sex toys, group sex, amateur, teens, interracial, old and young, bit tits, petite, etc... Again, it's the content of the Free Site - not the sponsor.
Also, most of the LL owners like to see submissions to a variety of cats so any one cat isn't over saturated - especially with one style FS.
Since you use a general recip with me, I can look at the FS and place it in the cat I feel best - I'm happy to do this but I don't get thousands of submissions per day either.
No problem promoting various sponsors - try a few and see what works best for you. Many submitters have a number of sponsors they promote.
I don't have a preference for recips, graphic or text, as long as they are executed properly. take a look at this thread
http://www.greenguysboard.com/board/...ad.php?t=44187