SunPump panels require equal flow so each panel contributes the most it can. Equal or balanced flow is important on the lower liquid tubes because liquids do not compress and follow the path of least resistance, so the best approach is a manifold.
The general rule is to Tee pairs of panels, using the top illustration below, and to increase the tube size one size with each Tee to match the line set size. (i.e. 1/4" to 3/8" to 1/2").
The flow through a Tee is more in the straight path than the side branch, which can be used when three panels are being piped with one panel off the side branch, and two panels Tee'd equally downstream from the straight through part of the Tee,, delivering roughly 1/3 of the flow to each panel. Another method is to use a round distributor with equal tube lengths to each panel connection.
What about Reverse-return connecting? It works with fluids, we are not so sure it does in fluid-gas flows so have some caution. A SunPump on Dogwood St. in Nanaimo has 8 panels (4 column x 2 rows) connected in Reverse-return, and is doing fine while we continue to monitor the performance to compare it to other installs.
In another Article we will illustrate panels connections for 4, 6, 8, 10, and 12 panels. 2 panels are simple, center supply and each panel connects to the Left and Right end of the Tee, as shown in the top image above called Equal.