though thinking about it and think it's a little lean. turning the A/F screw might sort it out but not sure
The A/F screw only affects the pilot circuit mostly and only a smaller amount as you move onto the needles and mains. So it depends on where about in the rev range and your throttle position that you believe to be still lean.
it behaves fine on the blibb test you said in a different post.
This suggest that you have the A/F screws set right according to the pilot jet size you have installed.
and the spark plugs are quite light in colour
You need to be careful judging things by spark plugs unless your doing a proper plug chop at the required rev range and throttle position your testing for. If you just go out for a ride and then pull the plugs when you get back your likely only going to get a reading from the bike standing at idle on the pilot circuit. Not only that but modern day plugs like Irridium are not as easy or as accurate to read compared to the older style classic plug.
Your better off using the choke as a testing tool to determine if lean or rich. Pulling the choke (technically an enricher) richens up the mix. Only pull it a very slight amount out otherwise this can also be misleading as you could just flood things.
TBH with a full system including header pipes (downpipes) you are better off doing a single dyno run to see how things are. As it stands you don't know whether the full system is affecting the top or bottom end and how. They are all different. Otherwise it's a lot of guesswork and a learning curve along the way as you begin to realise what feels rich and what feels lean. Even this can get confusing at times and you need to now what circuit within the carbs this is happening. On that note I have not seen Scorpion header pipes so a picture would be nice, especially of where the two cylinders join up.
You could try the 50's and then set your A/F accordingly and see if these give you better or worse performance but remember the pilot jet and A/F screws work together. Think of the pilot jet as a course adjustment and the A/F screw a fine adjustment and stay within 1 and 3 turns out. Also by changing the pilot jet size this will have an affect on the needle height, so if you go richer on the pilot you may find that you need to lean of the needles a bit.
You will soon get used to pulling carbs and making changes.
Only make one change at a time or you may get lost in what needs doing. Have fun.
(:-})
One other thing, don't go drilling the extra slide hole as in dynojet instructions suggest as this usually upsets things and brings on the slides too soon and richens things up. But who knows, it may actually be beneficial with the Piper filter and using the dynojet base settings. Personally I would try things without drilling the hole first.