Early TV175 Carb - MB21 BS5

I have a 1960 TV175. It has the original carb.
Edit - got the original jetting now thanks, all is correct there.
What is the best airhose to use with the standard MB21 BS5 carb. I'm trying to use a series 2 one but this doesn't seem to fit very snug on the carb. I can't see anything specifically listed for sale as suitable for TV2? Is a normal series 2 air hose ok?
Also, I can't find many good diagrams for the carb online. So when servicing, I am not sure if the carb top should have a seal/washer fitted.
I am suffering symptoms of an air leak. Carb is well serviced and jets are all clear, and beginning to cast my eyes onto the carb top/slide/needle. None of which seems to be in a bad way and free from excessive wear.
So:
Should the carb have a seal fitted to the carb top.
What faults with the carb could present the symptoms of an air leak?
What is the best airhose to use with the MB21BS5 carb?
Edit - got the original jetting now thanks, all is correct there.
What is the best airhose to use with the standard MB21 BS5 carb. I'm trying to use a series 2 one but this doesn't seem to fit very snug on the carb. I can't see anything specifically listed for sale as suitable for TV2? Is a normal series 2 air hose ok?
Also, I can't find many good diagrams for the carb online. So when servicing, I am not sure if the carb top should have a seal/washer fitted.
I am suffering symptoms of an air leak. Carb is well serviced and jets are all clear, and beginning to cast my eyes onto the carb top/slide/needle. None of which seems to be in a bad way and free from excessive wear.
So:
Should the carb have a seal fitted to the carb top.
What faults with the carb could present the symptoms of an air leak?
What is the best airhose to use with the MB21BS5 carb?