Every single manufacturer of metal roofing publishes a technical manual that describes the recommended techniques for finishing all edges of a metal roof with their product. Did you review the manufacturer's recommendations for drip edge? Likely they sell a special drip edge piece that should be installed under the roofing. The Advant-Lok roofing that I've used has a special drip edge with integral cleat. The lower edge of the roofing panels is folded under and slips over this cleat to anchor that edge. This way all fasteners are concealed and there are no penetrations or potential leak points.
When all else fails, read the directions.
Before I installed standing seam roofing on my house I got a couple of manufacturer's installation guides and then went around looking at existing SS roofs.
Almost none were installed as recommended.
Screws at the eaves, screws at the rakes, screws at the hips and valleys.
All of which defeat 2 of the big advantages of SS.
No holes penetrating where water is and no transfer of expansion and contraction forces to the screws which works them out and makes them eventually leak.
