Bidding System - Benji ACOL

The differences between Benjaminised Acol and Basic Acol lie in the opening bids at the 2-level.

2C shows 8 playing tricks in any suit or a balanced 19-20. 2D is a relay in response.
2D shows the same as a Basic Acol opening of 2C and 2H is a relay in response
2H and 2S are weak twos as per SAYC and 2NT in response is usually used as an enquiry so that opener bids 3C with poor points and a poor quality suit, 3D shows a good suit but few points overall, 3H shows good points but a poor suit and 3S shows a good suit and good points, and 3NT shows AKQ of the suit and therefore virtually nothing else! These are known as OGUST responses.
2NT openings are now 21-22 balanced (though some play 19-20 balanced and with 21-22 open 2C instead)

A small number use 2C openings for a balanced 20-22 and now open 2NT with a weak hand with 5+ in each minor suit, but this is not standard