I suggest you both read David Surdam's book on the economic effects of the blockade. It is the latest and perhaps last word on the subject. Surdam notes a lot of things, but basically says 1) the Brits surmounted the lack of American cotton by switching to wool and other, albeit more expensive, cloths; 2) New Orleans was the depot for shipping 80% of the prewar southern cotton, and that a blockade of the MS River alone essentially strangled southern exports because the existing rail lines were inadequate to ship large quantities of cotton or anything else from the MS River valley to Mobile or Charleston; 3) the "interior" shipping path for Trans-MS goods was down the Red River and then up the MS River to Vicksburg or Memphis, bypassing New Orleans; and 4) as serious as the MS River blockade was to southern exports, it also strangled the intracoastal shipping of TX cattle to VA and the east, putting further strain on the inadequate rail/river steamer system.