Chris, the pilot screws will have neglible difference to mixture & plug colour at anything much above tickover.RD04 or 07.
On RD04, adjustment screw require the tank off - or at least raised.
There is a screw left and right cannot remember which side is front and which is rear but it will be obvious. You Screw it right in and then unscrew it by a set number of turns normally. But if you know one is specifically out then I guess you could just unscrew that a tiny bit more and see how it goes. Once you have done the adjustment you have to balance the carbs again.
Makes a big difference.