So I saw a documentary once and a few scientists got together and collected air temps from around the globe the week after 9/11, when virtually all air traffic had been halted. They granted that it was only a week but noted that the temperatures were on average 1.5 degrees Celsius higher, if my memory serves. It might be worth inputting a few less clouds from air travel(I've no idea just how fewer flights there are right now or the actual amount they might contribute to dimming) over the next few months and see if that nudges your models. I wish I remembered which Doc' I saw it in, it was just a very brief part, it might have been Gore's Inconvenient Truth.