Larry, I left a slight amount of overhang. Maybe 1/4 inch but probably less. Here is what I experienced as a result. I sanded the edge of the acrylic such that it has a 45 degree edge on it. I would recommend that the underside of the acrylic not bridge that gap. This helps the number one rib slip in and under the acrylic edge when the wing is swung and pinned to the airframe rather than the acrylic catching against the number one rib. When I opened the wings up at my condition inspection I found that my Oratex finish tape on the wing was bunched up due to the flexing of the wing where it contacted the acrylic. Thankfully all I had to do is heat up the finish tape and flatten it down again. I then needed to sand the acrylic a bit more so that the contact points were lessened. I had to fix only about three inches between the two sides. At 235 hours now, it all seems fine.
Im not sure all this addresses anything whatsoever but I envisioned rain and hose water going right through that gap. I don't have any water make it through having done it this way.