I would have only 5 on a circuit. What is it that limits the circuit to 4 -5 fixtures?
Without looking at the light specifications, I can't say for sure... so take my comment with a grain of salt.
When some of the "linkable" LED lights are used together, it's assumed that when they are linked you have power to light number one, then power flows through the light to number 2, through to number 3, etc... 1-2-3-4. The wiring in the light can only handle so much power before it burns out, so the light manufacturer will tell you the maximum you can hook up in a row.
For example, if a single light was 60 watts at 120 volts, it pulls 0.5A alone. The next one in line also pulls 0.5A, and so on. The problem is, light number one might only have wires rated for up to 2.5A total... so you'd be at the maximum limit at light number 5. Light number 6 would heat up the wiring beyond the safe levels, and let the magic smoke out.
Now... you could connect a bunch of these lights on one circuit, and depending on what size wire you ran would determine how many lights you could have on that circuit total.
So for example, if you ran #14 from your breaker panel to a square box, you could connect to "String A" with lights A1 through A5 in a row. Then continue the #14 to the next box for "String B" with lights B1 through B5, then over to String C for lights C1 through C5. Each string would pull 2.5A each, or 7.5A total on your one circuit. Like this:
Power
I
Box 1 - Light A1 - Lt A2 - Lt A3 - Lt A4 - Lt A5
I
Box 2 - Light B1 - Lt B2 - Lt B3 - Lt B4 - Lt B5
I
Box 3 - Light C1 - Lt C2 - Lt C3 - Lt C4 - Lt C5
You can do variations on this, like having three strings on three light switches, but still on one circuit. Or individual circuits feeding each string, etc...
Hope this helps.
Mark