Yeah, it's hard. Pull the linkage off of the motor, if you haven't done it already. Then you just have to keep trying. It helps if you have someone else looking through the hole who can tell you when they see the end of the linkage. Might be easier if you remove the hood, too. But basically it's just a lot of fiddling around.

In theory, you can reinstall the driver's side first, which will limit the motion of the linkage and should put the passenger's side in roughly the right place.

If you're removing the wipers on purpose, you can tie a piece of string to the passenger side linkage before you remove it. Then, when it's time to put the linkage back in, you just pull the string.

If all else fails, get a ten year old to help!