You need to work in RGB mode!
go to File > Document Color Mode>set it to RGB from CMYK.
you will NEVER ever get good colors out of cmyk
Spot colors can give you superb results but very hard to try. It will always print a different shade what you see on the screen!
First of all spot colors won't work if you have any layer with transparent background. can't even use drop shadow effect!
Mostly I use spot colors for perfect grey or black colors. bk21a will give you perfect black. it won't use any other colors but the black ink. You want perfect grey you gotta find the best one. you gott abasically do test prints to find the one you like. I always do test prints when i work out of illustrator. Last time I had a huge gradient and instead of orange it was more like peach once it was printed. wasted 10yd or material
When you use spot colors you have to check the option in versaworks! You can also change the colors in there too. So you might pick a red color you like but in versaworks you realize that it uses some amount of other inks besides magenta and yellow. or maybe the M and Y not on %100 or whatever the issue can be you can either pick another color in versaworks and you can see each spot color uses what percentage of which inks or you can manually adjust the percentages of each ink. you just have to make sure you chose convert spot color to the new one.