Stick,
Your weight difference between solo and two up as a ratio is very different to mine. your pillion and luggage weigh roughly the same as you, almost a 1:1, my ratio is 1.45:1.
This would be the same as you having a pillion and luggage of 142kg if you sprung your bike for that weight you would be over sprung for solo.
I did go through the questions with the TT team and were very helpfull but I knew from experience of having after market suspension on 4 previous bike what to expect, the stock shock D-ESA is a good idea, not until you replace it do you realise how much better it can be.
Bang on with that , the new system is spot on and find it perfect , I did adjust the L and H speed compression as its a personal thing , spring wise great.