I am uncertain how well 'Orange Dream' responds to air layering. Some JM are very reluctant to strike roots. Certain JM's are known to be impossible to root. Others root easily. 'Orange Dream' is relatively new, not on Vertree's list, so I don't know if it roots from cuttings or air layers. Anyone have hands on experience with 'Orange Dream'? Does anyone know if it roots from cuttings, or if it can be successfully air layered?
As an alternate, or an additional project; Why don't you go over the list of cutting grown JM cultivars available at Evergreen Gardenworks and by yourself a maple cultivar already on its own roots. Cheaper and less hassle. The cuttings may be small, but pop them into 3 gallon containers in spring. and likely in as few as 2 or 3 years they will catch up to the air layer you would be trying to make from a 3 gallon grafted plant.