In our previous house (not in TV) I used a plastic (PVC?) product with about 3/8 or 1/2 holes over the entire surface. These snapped onto the gutter and slid under the last row of shingles, and worked great for the 3or 4 years before we moved. We do not need these in our TV home so no experience, but I do not see any reason why they would not. These were around $5 each (I think) .
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Pennsylvania, for 60+ years, most recently, Allentown, now TV. 
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