Not experienced but I think the trick is probably to follow the guidelines they give and not stress about the rest of it. They say this on the Strange Chemistry page
"The notes above will tell you everything you need to know about submitting your manuscript. IF ITíS NOT MENTIONED ON THIS PAGE, ITíS NOT WORTH WORRYING ABOUT, SO DONíT FEEL YOU NEED TO QUERY THE SMALLEST DETAIL. For instance, if you telephone us to ask what font to use (this has happened) weíre probably not going to want to take your manuscript further."
So, I'd say:
- use any font you like as long as it's legible (so probably Times New Roman or Verdana or something along those lines - not one of the stupid curly fonts)
- depending on the font (Times New Roman comes out small) the size should be sensible -- so probably around size 12 (11's probably okay if you're using one of the bigger fonts) -- don't send it in size 6 or anything silly. They're going to be able to tell you've got thirty-eight character profiles, even if they fit on half a page in size 2.
I haven't finalised my submission yet, but I'm doing the five main characters (160 words or so in total) and then my plot, which is currently 650 words.