Help in Creating Multi-griddlers

I use Adobe Photoshop CS.
 
When I create a multi with one background color in all parts I use Indexd Color mode. It gives me the option to select number of colors.
 
If I want to have different background colors for the parts I work with several files in photoshop, the main one is the whole image file. In Photoshop there is an option to put grid lines. I use it for the size of the parts. Then, according to the grid lines I "slice" parts from the main image. I check and change every part until I have max 8 colors, and then I bring it back to the main image. I do it because I must have the same colors in the whole image. I can't have some red in part 1 and another red in part 2. All reds must be the same. Sometime I need to change colors in parts that I already checked. That is why I bring back the parts to the main image.
 
After checking all the parts and having them in the main image I slice the image again. This time it is a fast task: slice, create a new file, save as 0/0, 0/1. Then I upload the parts in workshop, validate, send. If I am lucky it is a fast task too, unless I have a part that is difficult to valitedate.
 
What I am trying to explain is that I do most of the work in Photoshop. It is not a simpler process, but after doing it a lot of times it isn't hard either. In noticed, though, that creating multis may take more time than solving them. You can check it too. Look at the mid-time of solving a whole multi and compare it to the time it took you to create that multi. I believe you'll find the same result: it takes more time to create. But creating is fun, isn't it?. I like creating.
 
Eli

You don't need to do it by eye. I don't know if Photoshop lets you do this -- I use Photoscape -- but I draw a crop box in the upper left corner, size it to the number of pixels I want, and save the area in the box as a new file. Then I expand the box to double width so I know the right edge is in exactly the correct place, and then move the left edge until the box is the right size again.

As for picking color palettes, that's easy. Photoscape has a tool wherein you can move the pointer over a color and get its exact composition of red, green, and blue. You can change that composition in the griddler workshops by double clicking on the color then clicking on the rightmost tab. A perfectly mechanical way to copy the color, if you don't have an eye for it.