Russ, do you have some photos or a link to share on what that looks like?
I guess I didn't take pics of these yet. I'll see if I can grab a pic or two today.
...Ok, went out a took some quick pics. I did this install not too long before the new "Select Direct Micro" board came out, which I may have used instead of the original "Select Micro"... although I'm not exactly sure how the speaker would've been positioned/arranged if I did. In this install, I was able to fit a 9X16mm, 1W max speaker with scratchbuilt enclosure where the original headlight block/shroud went. The Select Micro with its outer wrapping (snugly) fits in the stepped-out/wider section at the rear of this loco's long hood...
With shell back on showing the nose headlight and cab gyralight in operation. I may eventually do more to block light leaks in the cab and, if I get really ambitious, I may add separate LED's for the numberboards. Right now they illuminate off the gyralight, which actually doesn't look all that bad since the effect does not go real dark between flashes....
I currently don't install caps/keep-alives in my locos. So far, they seem to perform surprisingly well without them and with only the occasional sound dropout.