If your point-on changed from 30 yards to 40 yards when you switched from right to left-handed shooting, then your anchor point must have dropped somehow, or maybe your bone or eye structure is slightly different on the left side of your face. If it were me, I would tune the arrows optimally for the bow, and then see if I could get a new anchor point that would put my point-on at 30 yards again. I say this because changing your anchor point should be a minor adjustment compared with switching from right to left-handed shooting.
If you increase your nock height, you will drop the point of impact of your arrow somewhat. If your optimal nock height was 1/2", you can probably raise this to 3/4" without adversly affecting arrow flight. Your arrows will be tail high, but a little tail high is okay and prevents fletching contact with your arrow shelf.
If your bow has adjustable tiller, like the Dalaa, you might be able to adjust the tiller to eliminate the nock high you will get from raising your nock height. Normal tillers are either even for shooting three fingers under, or maybe +1/8 for split finger shooting. I guess I would try moving your nock point up some, and then shooting a bare shaft to see what effect that has on your arrow flight and impact point. Then change your tiller by 1/8" and see what effect that has on your arrow flight. If it gets worse, then change it 1/8" in the other direction and see what happens.
Another alternative approach would be to use a variation of string walking. First, tune your arrows optimally for your bow, without worrying where they are hitting. Then, set an additional nock 1/2" below your arrow nock. Your string fingers will go under the new nock. This should drop your point of impact, and you can experiment from there to see exactly how far below your arrow nock your "string finger" nock should go to put your point-on at 30 yards.
Finally, as far as people setting up their bows to shoot where they look, I think it's generally the other way around. People tune their bows for good arrow flight, and then shoot them enough to where their brain finally gets programmed to point the bow in the right direction so the arrows hit where you're looking.