The 3/16" or AN-3 with 0.049" wall thickness (the thickest I see in the McMaster-Carr catalog) would have an ID of about 0.090". The -3 fittings have an ID about the same or slightly larger. One would need to do a good pressure drop calculation or a test to see if the combination of 3/16" fittings and tubing would provide the same restriction as a 1/16" orifice.
Hoyt
