dash lights issue

I'm confused as to where you have power connected. I have 2 sets of 3 gauges in 2 cars hooked to the male spade that would be directly behind the instrument fuse in you fuse box.
I'm glad that you have had no problems, but the fuses are sized for the load that they are expected to handle. If you add things to the spade that you are using, you are adding to the load on the fuse because you are adding them after the fuse (power for the addition goes through the fuse). To avoid this you can add things to the opposite side of the fuse (in effect before the fuse) and protect the added wiring with a fuse in that added wire.