Indiana and Colorado spinners each have their place in this in-line systems. A good way to stay versatile is to use the quick change clevises and to carry several colors in both the Indiana and Colorado blades and in sizes 2, 3, and 4. The beads used in rigging these set-ups should also be carried in several colors. Most of the rigging I see if for walleye and generally has only one spinner. Certainly more could be added but the amount of drag created is proportional to the added spinners.
Colorado blades give more "thump" as they rotate and work better when the water is stained or dirty. Colorado blade are easier to get started turning at slow speeds. Personally I'd start out with a Colorado blade of about a size 2, maybe a 3, color based on water conditions. If the trolling speed gets higher than about 1.5 mph I'd switch to the Indiana blade as they spin nicer at higher speeds. Clear water blades in silver is dandy. Gold works in low light and when the water has some color. Your fluorescents have a wide spread of use and work well in many water and light conditions. Something I don't fall prey to is the use of blades with nice little fishy pictures on them or scale patterns....you get the idea, Color and or flash. Period. The fish can't see the decals on those blades even if they do look good to you. In blades, basic is best.
The beads that I mentioned. Go with gold, silver, chartreuse in both opaque and transparent, fluorescent red in transparent and opaque, fluorescent orange in opaque and transparent. 3/16" is a good all-around size to carry.
Tie a GOOD ball bearing swivel to your main line. To it tie on an adequate length of 10 or 12 pound fluorocarbon line to carry the spinner and beads finishing with hook or bait of choice. To stop the sinner from falling all the way back to the hook, simply run the line thru the last bead then up and back thru the bead again. If you use more than one spinner, do this at the end of each run of beads behind each spinner/bead cluster. This also allows you to quickly adjust the distance from the spinner to the bait, something that at times becomes a part of the over-all equation. DO NOT use braid as the rigging line for the spinners. Braid will wear quickly where the clevises run. The fluoro is crystal clear and allows only the beads and spinners to show....very effective.
As a rule, the crappies I find hitting spinner rigs when I am trolling walleyes are larger fish and are aggressive. If crappies are neutral or negative, I wouldn't waste time on trolling as a means to catch them. In states or waters where multiple lines can be used spinners can be run at various depths using various color combinations to search for active fish. While I am a proponent for artificial baits, don't hesitate to run a couple of minnows on spinners. The "Gulp" line of minnow baits in 2-1/2" size is an excellent alternative to live bait while running spinners.
Spinners take some getting used to. Almost always it will come down to trolling speed, or color combinations, or spinner size, or a mix between some or all of these. Make no bones about it though, spinners can catch some ungainly hogs when other styles of fishing are handing you the skunk and those spinners can put some bonus fish in the basket too.
Look up www.JBLures.com on the internet and look thru the selection of blades and beads and clevises found there. They offer a whole new world of everything a spinner guy could want including pre-ties so all that's needed is to snap the rig on the swivel, bait and go.