Dave,
The 620`s should be here wed/thurs, it will be interesting to see weight wise.
I will have a small air tank extra, but no servo`s ,i use the jet-tronic single http://www.airpacmodels.com/twe/prod...products_id=41
And no extra linkage, but the 620`s dont look light i have not used this small of a series befor so i am not sure.
I hope i am even close to your current weight.

-Jason