While there are a lot of posted warnings about the position of the centerline versus the carb, this is not quite as important as it seems to be made out to be.

Yes it helps prevent siphoning, and hydrolock, but in actual practice even a 1-2" variation has little to no affect on the engine performance once it is started, on a properly plumbed plane.

If it did we would not be able to fly uplines and downlines with the ease we do now... even on unpumped engines...

Then there are the tail draggers that effectively lower the tank position when they are sitting with the tail wheel on the runway, but raise it in level flight, etc...

So while it IS best to do as the diagram says, if you cannot do so exactly, don't worry, it is not THAT problematic...