Bonita: You're in very, very, very good hands with Pinnacle... and in fact, for horses you won't find any better.
One thing to keep in mind is that with them you won't get a chance to bet so late as when the horses are beginning to load:
what i do is treat 1 Min. to post with them, as 0 Min. to post elsewhere-- once you see the 0 Min. to post with them, immediately get that bet down, you'll have at most another 30 seconds to. You can always pre-enter the bet in much earlier & hold it-- then send it later-- it helps if your pw is not too complicated, for quick entry-- if it is, you can have it printed in an open notepad or clipboard utility: ready to COPY(CTRL_C)... when i need to send in a bet, i just Paste(hit CTRL_V & enter).....
Another thing i do is atomic sync my computer clock before each daily session-- there is a good app here for that, in the downloads section:
http://www.worldtimeserver.com/
but i close it manually with File / Exit, so it doesn't run in the background(even though it's tiny) consuming resources.....
Good Luck to you-- check out their Horse Matchups btw-- you have to exit Horse Racing & find them in the Propositions / Futures:
http://www.pinnaclesports.com/guestContestLines.asp?ContestType=Horse%20Matchups FYI they get taken down @ 30-45 min bef scheduled post.