I just can't understand why we are still giving people this advice. It's just not true. We just touched on this discussion in another thread so I won't go into all over again. But I challenge you to go to ANY well respected furniture maker's shop and find a table top glued up with 3" strips. You won't, and they'll look at you like you're crazy if you suggest the 15" boards used in their table will warp because they aren't quarter sawn or the growth rings alternated.
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Forgive me for being "old school", but that is how I was taught back in 1967-8 in high school shop and again in Woodworking 1 and 2 in college as part of my Industrial Arts Teaching major. I also owned and operated a furniture factory for several years. I would guess that I have glued up more solid wood panels than you will see in your lifetime. My experience tells me what I wrote in my first reply. I don't go by what others say. If you don't like my advice. That is your choice, but I do know that flip-flopping the growth ring direction does lessen the warping problem when gluing up panels. Another thing...factories that glue up panels very seldom use boards wider than 4".
As for the 15" planks used by some furniture makers, Most of these wide planks come from a center cross section of the log and therefore do not have the curvature of the growth rings to distort (warp or cup) the plank. If you go to any lumber yard and look at 2 x 12 planks you will see the affect of warping on wide planks. All you have to do is look at the growth ring pattern on the ends of the planks and you will see what I mean.
Now, back to the problem at hand...the questioner uses the word "warped" along the length. That is the wrong term. Warping (cupping) happens across the width of a board. Bowing happens along the length.
For bowed boards to be used in a glued up panel, they need to be cancelled out. It is best to alternate bow up, bow down. I would put the bowed boards in the middle of the panel. If they are put at the outsides of the panel, they could cause the panel to twist.
The small amount of bowing showed in the pictures should be able to be pulled out as the panel is glued up by starting the clamping at the middle of the panel and working toward the ends. At the ends, use C-clamps to bring the boards into alignment. You can use a scrap board across the panel on top and bottom along with the clamps to draw all the boards into alignment.
You can use a spline or biscuits to align the boards, but I don't like the hassle of lining up biscuits while glue is drying on big panels. We had a glue joint 2 sided jointer at our factory that put a small tongue on one edge and a matching groove on the other. When we glued up the panels we would pound the boards into alignment with a mallet so the tongue and groove mated.