oak worktop minimum worktop to leave after cutouts

Hello,
I am fitting a 620mmX40mm oak worktop and am wondering how much worktop should be left to maintain strength (integrity)? please see attached PDF.

What I have in mind is drawn in the pdf file.
Basically it is a Franke sink under mount sink that I intended to fit as a drop in. (dotted line is cutout for sink) I intend to remove some wood from the cabinet top front member to move the sink forwarded by 30mm. This would leave about 80mm of worktop at the front edge and about 116mm at the back edge, this I think should leave enough worktop for strength. (common sense handling etc.)
What worries me is where I would like to place the tap as this would reduce the total amount of worktop at the back edge to about 80mm where the tap hole. What do you think please?

One idea I to add a piece of 50mm X 50mm wood (glued and screwed) under the back edge of the worktop for the run of the sink (plus some) to give it more strength.

Other option is that I really don't like too much is to put the tap at the side of the sink.

Ideas please?

imk

 

Many thanks, thats good to know that something is going to plan on this job ;-}