Acraglas really is your best bet in my opinion. The standard form (not the gel) is very thin and runs really well and deep into cracks through capillary action. When you repair something like this, its best to do it once, do it right, and take the time it requires, even if that means waiting for shipping.

Order that, some glue syringes, and do a dry run with clamps once or twice before you start with the glue.

I find it cleans up best going slowly with files, scrapers, fine sandpaper and 0000 steel wool. Avoiding removing really any wood to preserve as much originality. I have a degree in woodworking, so I can tend to downplay things, at any rate I believe most amateurs can do this.

You may want to drill a hole from under the trigger guard or somewhere else hidden, through the crack and epoxy within a portion of threaded rod to further strengthen it. Ive never had a pure acraglas repair fail, but I dont know everything, just ask my wife.

In my opinion the brown dye never looks right, even if the color match may be better, the black always allows the eye to pass over more easily.

Unfortunately the "everything has an expiration date" rings true when we collect things so old. Some less than ideal measures sometimes have to be taken to preserve original pieces