Don't have to much of a problem with your Mod, but would A) bend the float arm so always has a 1/4 tank when reading empty, B) advise owner of possible issues.
With regards to your comment
>> From memory, when I performed the "mod" I introduced the return pipe inside the swirl pot. This would have the effect of maintaining an abundance of fuel inside the vessel. <<
Surely this can not increase the level of fuel without a venturi, as Fuel is being removed and returned to the pot in same quantity ( less engine use ).
Cheers Aidan