Thanks GF
OK, it looks like the FAA will allow a deviation from the weight provided the objectives of the training can be met in an alternative device. So an ATPL skills test on a Business Jet under 40,000LBS looks possible provided the required flight training hours and ATPL manoeuvres are covered.
However it looks like the 30 hours of ground school will stick. Although a pain, I guess it's not 'unfair'. Since an EASA reciprocal conversion will require lengthy home study, at least 2x of 2 weeks 'refresher' training plus 14 exams! I just hope that the CAE's and Flight Safety's of the world have the syllabi ready.