Very helpful article. I found virtually the same issue on the same side (passenger side) of my 2002. The only things that I would add are...
1) Use a normal household vacuum cleaner over the drain holes to suck out any debris which might be clogging it. Using this method there shouldn't be any need to stick tubes or wires down the drain holes. Alternatively, use compressed air
up the drain tubing -- i.e. from the bottom of the car. You still might want to use a vacuum cleaner to vacuum up anything that comes out. I wouldn't use compressed air
down the drain because if there is a clog, pushing harder on it may not be helpful, and the compressed air will try to find a way out, and may actually create a leak at the weakest part of the drains.
2) I am going to make a point of vacuuming the area under the folding roof once or twice a year. It only takes a few minutes, and if there is no debris in that area, it won't end up clogging up the drain. I'd most likely do the area around the front drains too.
