Hi, are you still interested in 1x1's?
If you are:
I'm not really a fan of fandom rp's (mainly because I like to come up with a (semi)original plot and lore and all that), but I can do a fandom rp's if the setting is interesting.
I don't really know if I have a post for you as an example (atleast not in English), but I can come up with one if you would like to see one. As for grammar and spelling, I'm not really sure what you would classify as 'proper' grammar. Since my main language is Dutch, I may just make some mistakes, but hopefully that won't bother you too much if you are interested :)
As for post length: I usually write around 500 words, sometimes more if I have inspiration and the worldbuilding and characters are fleshed out.