Ha ha, poor man's compendium.
I too use the dark slide in exactly the same manner.
I saw compendiums used a lot in the studios and always noted just how fiddly they were to get things just right, more so if you were using CC filtration in the filter slot/opening some of the compendium hoods had. As a result I haven't been a big fan of one for the type of general photographic work I do.
Still, if I ever came across a compendium hood for the right price, I would probably jump at it.
I have negatives with fingers, dark slides, bellow pleats, the edge of my hat, and once, almost half a hand being outlined. Those days are generally behind me, but......