A couple of posts ago I mentioned fishing different colors and stages of life in the midge world.
Although, fishing more than one fly on a rigging can be quite rewarding, it has it's problems also. Problems such as the secondary tippets (the ones you add to carry the additional flies) fouling the primary tippet or leader.
To combat this, I started tying an overhand knot in the added tippet after the added tippet was secured with a surgeon's knot. Clipping the short tag end of the added tippet, I simply take the fly carrying end and make an overhand knot around the primary tippet. This seems to hold the added tippet perpendicular, or at a right or left angle to the primary tippet.
Another thing to consider in saving yourself a lot of grief when fishing more than one fly is the cast you make. If you are proud of that tight narrow loop you can cast, then you might as well leave it at home when fishing tandem rigs - it's only going to cause you trouble.
When fishing multiple flies you need to throw those big ol' ugly open loops. Yes, they're big, ugly, slow, and lazy, but, they will keep your added tippets or flies from fouling each other. My friend, Bruce Dixon use to call these casts loopy-loops or circle casts.
And then there is the distance you are casting. When fishing multiple flies I have never found a reason to make a cast beyond twenty feet. I'm fishing the water near me because something I've seen has told me there is evidence of midge activity there.
When fishing a trio of the midge world I tie the weighted fly on the bottom or the deep column fly, let's say a beadhead Zebra. Judging the depth of the water and the speed of the flow, I may or may not add split shot about eight inches up.
For the second or mid column fly, I'll choose a midge with a more pronounced thorax which simulates the pupa stage.
And finally, as the top column fly, that is set quite shallow below the indicator, I choose a midge pattern that simulates a shucking or escaping midge.
One thing for certain is that the way I choose to present multiple flies is not perfect. I mix, match, don't mix or match, present one color in contrast with another color in the different columns. Some will argue what I do is plum silly... and that's okay. For me, it's all on the pathway of discovering all there is about fly fishing and particularly fly fishing using the maddening world of the midge.
Good luck to all of you in pursuit of trout by way of the midge.