earlier than that you may not be able to commission it. For sure you will not be able to access all the features (most of which are for fishermen and are relatively useless, but some are the fine tuning parameters). It is quite clear from the Raymarine site that an ST6002+ will work. I think anything on an ST60 system that can engage the pilot still will do it (this is a Seatalk 1 datagram). I went the other way, had an ST70 control head on an S3G pilot (tech support said it wouldn't work, but it did).

One peculiarity of the ST70 head is to engage steer by wind you have to go one step down into the menu structure. With the ST6xxx heads, you can push two buttons at once and directly engage steer by wind. Other than that, the ST70 head is very nice.

If you get this installed, do play with the "response" setting, which is the most basic adjustment. I find that it steers fine and is less frenetic set to the minimum of 1. It powers up default at 5 and goes to 10 (not 11 ). In really nasty conditions I have to turn it up to 3.