I have the Makita with 3 short rails. I contemplated the long one, but from my research before I bought everything, the longer the rail, the more likely there would be deviation along the length - they are extrusions and not machined after all. The reason why I have 3 is because my intent was to get 2, but one was slightly bowed. I forget by how much, but I think it was around .003ish at the center, so cut it shorter.
As far as connecting the two "regular" rails, at the time, Makita USA only sold the connectors in single packs, which was pretty stupid, considering it was sold as pairs everywhere else in the world, so I bought 2, which was much more stable.
I found that connecting two pieces worked great by using a straight edge to bridge along the bump that the saw tracks on before tightening, and ignoring the fact that their might be a small gap in a portion of the connected edges because the rails are not exactly 90 degrees.
As far as connecting the two "regular" rails, at the time, Makita USA only sold the connectors in single packs, which was pretty stupid, considering it was sold as pairs everywhere else in the world, so I bought 2, which was much more stable.
I found that connecting two pieces worked great by using a straight edge to bridge along the bump that the saw tracks on before tightening, and ignoring the fact that their might be a small gap in a portion of the connected edges because the rails are not exactly 90 degrees.