I have done enough oil changes with my Rav that I can pretty much eyeball it. I take a 5 quart jug of Mobil 1 and pour in a little over 4 quarts (judging by the hash marks on the side of the jug) and 90% of the time I get the level to the full mark on the dipstick on the first try. On a couple of occasions I've had to add a little more, but it's easier to start with less and add a little instead of pouring in too much and having to take some out.
When you go to check the dipstick, you should first let the engine sit for at least five minutes to let the oil settle back into the pan. Then pull the dipstick, wipe it down with a clean towel, stick it back in for a second, and then pull it back out. When you pull it back out, hold it sideways to get an accurate reading, and always look at both sides of the dipstick.
As for the metal oil baffle, it's there for a reason, otherwise the engineers wouldn't have put it there. Yes it would be nice if you could just sit the funnel in the hole, but I've never had a problem holding the funnel with my left hand and pouring the oil with my right.