Experimented with several methods for removing the outside edge of channel material. Band saw cut was too wide, requiring a good deal of dressing on the edges which removed more material that called for in plans; also difficult to repeat cuts. Dremmel also unreliable and not repeatable.
Setup a router table using a piece of 3/16" birch against the fence and an opening just wide enough to enable smooth, repeatable cuts along the channel edge. 'Forward' cuts from open end right to left. For 'reverse cuts' the channel was plunged against the bit with a push block then pulled right to left. Had two pieces that caught and pulled 1/4-1/2" of additional material through the bit.
After cutting channel to length and removing protective film:
Setup router table with 1/8" bit and scrap to trim the outside edge,
Channel held firmly against fence and cut to mark.