I use replacement stainless fittings extensively when the need or opportunity presents itself, always assembled with a blob of grease. On most occasions these are used on aluminium and have had absolutely no corrosion showing from the many hundreds I've fitted on Morgan's and Land Rover over the years. I don't dispute galvanic corrosion between these metals but simply and honestly confirm I've never seen any, noting it's likely to be mininal anyway if the greater area of the two is the aluminium.