vent routing

Your new slot opening is 18% smaller than the recommended opening (using my fingers to figure that out).  Check your input wattage and subsequent port noise.

Port bends are sometimes necessary.  You are doing the right thing by trying to design them to a minimum.  That is all that can be asked.  I would look at the maximum length that the port could get with just the one double 90 bend and enlarge the port opening to the point where that length would be achieved but not surpassed (you know a larger opening demands a longer length).  The larger port diameter would help to make up for the restricted air flow in the "kissyourbehind" turn.  But I don't know of any studies in this.

By reducing the recommended port opening already, you are setting yourself up for not only port noise but restriction in the port.  In the end, it may not be noticeable.  But how will you know it wouldn't sound better with a bigger opening?  Err to the side of reason.