Just checking in to clarify: we are in a similar situation except that we are simply transitioning how our product line is presented on Shopify and organized within TradeGecko.
We sell clothing, and so far the only Variant Option has been Size. Now we are adding Color as a new Option, and we are exploring ways to consolidate existing products which are only distinguished by Color.
@Priscilla, just to confirm your earlier response, is it not possible to consolidate Variants in a way that preserves their Sales History in TradeGecko?
From our perspective, we are only interested in preserving Sales History, MAC, etc at the Variant level. I don't see why moving Variants from one Product to another should require a deletion & recreation of each Variant and a reset of the associated sales data.