Marcel, for what it's worth I would suggest going with one product or the other but don't mix them.
CA glues work best when there isn't a big gap to fill. Yes there are gap filling varieties of CA but CA glue is rather brittle when cured and in thicker layers, even those as thick as a business card, tend to be brittle.
So my own choice would be for a slow cure epoxy that is thinned using warm air from a lower setting of a heat gun or seriously hot hair dryer. When heated this way the epoxy resin thins out so that it's like water and it'll creep along the most amazingly thin cracks. In fact you'll need to dam up the lower sides of the cracks with masing tape or similar to avoid it flowing down and out. And when cured epoxy has a little more resilience to it than the more brittle CA glue. When doing the cracks this way you'll only be able to do the ones on each side that will allow you to fill the cracks without them draining since when warm the epoxy is so thin.
So what epoxy to use? You want one of the clear types with about a 2 hour cure time. That'll give you enough time to work and the fact that it's clear means there's no fillers to help keep the resin too thick to penetrate well. So JBWeld is right out due to the fillers in it. You want a clear unfilled 2 hour formula.
As mentioned earlier after it's degreased and totally dry so that you can't smell any sign of the solvent you'll want to warm the stock for about an hour under something like a 100 watt old style incandescent bulb. It'll take that long to warm all the way through the wood. It should be very warm to the touch but not too hot to handle comfortably. That'll give you the best penetration of the glue to the deepest points. And when easing the glue down the cracks try to flow it in at one point in such a way that it runs downhill and displaces the air in the crack back up. That'll speed the filling of the crack. Use the hair dryer set on high to thin the glue to encourage this flow.
Acetone is a good degreaser for this as well as commercial autobody grease and wax remover from a autobody paint supplier. Lacquer thinner will also work well but will take a little longer to dry. And all this stuff really will do a number on the oils in your skin as well so DO wear the proper nitrile solvent resistant gloves for this unless you're just swishing the end of the stock in a can of the stuff. Keep swishing and lifting to drain and check the progress. Likely it's going to do a number on the oil finish of the stock but that's easily redone later.
Best of luck with the repair. The stock I did using this same method is working out fine. Mind you THAT one is on a Stevens Crackshot single shot .22....
