Anyone installing multiple Sunny Boys should be aware that it is no longer necessary to buy one Square-D Disconnect switch and wire two poles in series in for each inverter, in order to get the 600 volt DC rating. This effectively requires one disconnect switch for each Sunny Boy. Arghhhh!!

The good news is in Square D Data Bulletin 3130DB0301, dated May 2003, which you can download from their web site. According to Figure 2 of this bulletin, you may now connect one inverter on each of the three poles of their Heavy Duty switches such as Square-D model number HU361. So, if you have three Sunny Boys, you only need one disconnect switch.

Well , you might not think it is such a saving when you go to replace a single inverter and shutdown ALL of your solar production to replace the single inverter

I'd keep with the single disconnect per inverter for this reason

Im in LA DWP service area.
The city of LA, california requires separate a/c and d/c disconnects for each sunnyboy. While it may be nice to only disconnect 1 sb2500 at one time, I think the average or typical user will not have a need for this.

According to the code corner on the HOME POWER web site you can use the switch to disconnect up to three parallel PV strings using the one switch and use the three outputs to directly connect to the sunny boy(It has three sets of screw terminals for DC input.)