That will be fine, especially if you put the speakers in room corners or at least against the wall. The design works best in eighth-space or quarter-space. The difference in baffle size will change the step frequency, but placement near room boundaries counteracts baffle step.As for the port, position makes no difference provided the port isn't obstructed. The only exception is when the port is placed in a location where there is a high pressure standing wave node. Helmholtz resonance is unaffected by port location, but the influence of internal standing waves nodes is determined by the positions of the driver and port in relation to cabinet boundaries.