Kind of late in the post, but better late then never...:D
We have Miranda cards we can read off of. We can also have the suspect sign the card if she/he isn't handcuffed. If they're handcuffed we just write 'handcuffed' on the signature line.
Also there is case law that says you don't have to read them verbatim either. So even if you go from memory, and mix them up or change a few words, you're still OK, as long as you get the jist of them across. I'll look for the case law if anyone needs.
Be advised, I'm mean nasty and tired. I eat concertina wire and piss napalm and I could put a round through a fleas *** at 300 yards. So why don't you hump somebody else's leg mutt-face before I push yours in.