MIMF

I joined a heavy figured bearclaw sitka spruce top and went ahead and did the rosette and cut the sound hole and then (of course not before I started), I noticed that grain lines converged on the center line with the apex of the "chevron" pointing toward the neck. I know the common/best practice is to have the grain lines running the full length of the top (i.e. neck block to tail block) parallel to the center line, but I don't recall talk of the grain lines converging. I don't think it will make any difference structurally, but figured this is the place to find out.

How much are you talking about? If you had to re-joint this top, how much would you have to taper the joint to get parallel grain?

Not sure splitting/rejoining is an option with the rosette/soundhole done. If it's the "bearclaws" forming chevrons, I'd say that's normal & not to worry. If it's grain lines at a very acute angle (which I'd guess it is, since it didn't jump out at you earlier), IMO I'd also say chaulk it up, make a note so it's not repeated and move on.

I guess my concern is the strength of the top being able to resist tearing apart when it comes under full string tension. The angle is extremely acute (probably less than 1 degree). This is one of those mistakes that is a shame since the top was a nice piece of wood. That being said, hopefully I can forge ahead without worry. It is a guitar for myself so no worries there.

Post a photo if you can. Otherwise, I think it'll be just fine.

I think the only concerns here are cosmetic, that small amount of runout in the joint should have no adverse effect on the strength of the joint.

My first guitar build was a Stew Mac kit. The top came pre-joined and profiled. The top did not have straight grain, it had sort of a bow to it with a chevron in front of the bridge. This seemed to be against everything I knew about building guitars (which was not a lot at that time). I went ahead and used the top and it is still together/no splits 7 years later. Its a great sounding and loud guitar btw. So...I don't think you have too much to worry about.