I sympathise with the OP. Ilford Art paper isn't cheap. So is there a surface that is close enough to the Art paper surface out of the MG range of Glossy, Pearl and Satin that will enable the OP to get very close to the right exposure. Of course this relies on the MG IV emulsion being the same or very similar to that of Ilford Art. Is it in terms of exposure characteristics. Maybe Simon Galley will respond here?
I am sure that ideally you should do test prints on the same paper but how close would the quick and dirty test of using MGIV get him?