I can see why it got pitched, same cone shape filterbox the BB used, no way to get it in & out w/o trashing it OR split the frame.
I used UNI pods on the ones I did, right on the carb no velo tube. DelOrto does make tubes that screw on the VHB carbs.Velow's are 65mm part# D3100-55, for 45mm Part# D8348-55 There are 3 other short ones.
Got this info from DelOrto Manual 30.1
I just ordered a bunch of jets I need for tuning my moped & a set of Guzzi pilot jets I didn't have in stock.