[quote=@ManyThings]
Looks good, I'm up for playing. Do you have a preference between canon and new servants?
[/quote]

I have a preference for new servants. But if you're really stretched and nothing comes to you, I guess canons aren't that bad. Though if you end up wanting one that's also used in Fate/Go or something, you're pretty fine as long as you don't just copy directly from the wiki. 

Just don't directly copy one used in the anime and you're pretty good. 

One thing you can do is take a pre-established character and put them in a different role. Like putting Gilgamesh in Saber. (Example.)