I'm needing some help with the guide spacing on a 12 foot crappie dipping rod the ones I'm finding only go to 10 foot.

Length changes nothing other than the amount of guides, try spacing the extra guides near the tip 6 inches apart in the appropriate place, than continue the spacing you see in your 10 foot chart.

Jody,
For years, I have used the following method to set up guide spacing.

I take my blank with the grip and reel seat on it, and I have a roll of 1/4 inch wide tape to mark locations.

I just take the blank and press the tip against the ceiling, wall or floor. I observe the blank, and at the location, where I first notice a bend - I mark the spot for the first guide. Then, depending on the blank, I will likely place one more guide between that guide and the tip to carry the line.

Then, I go back to the press the tip method on a surface and note the location where the bend guides next. Another mark. Then, I continue on down the blank increasing the pressure on the rod to bend more and more of the blank marking as I go.

I will tape the guides to those locations and then run line through guides and tip top that is taped on and pull n the line and check the line flow and the distance of the line from the blank. i.e. I am checking to insure that there are just enough guides on the rod to have the line follow the contour of the loaded blank.

This is 100% effective and 100% correct for any rod blank.

Basically, you are looking for the guide locations such that the line follows the contour of the loaded blank. You need no more, nor no less guides than what you find using this method.

Of course, you still have to have the correct guide size and height at the appropriate locations.

But, in today's world using the 3 guide reduction, it is pretty easy to figure out the guide sizes and height.

Be safe