Looking at your store, and considering the hypothetical situation, in your shoes I might consider keeping it simple and not selling to the USA at all. Maybe with the exception of a few highly collectible expensive items that might benefit from the extra eyeballs.
Even if CDs pressed in the US come without tariffs, think about the amount of administrative work that would go into even determining the country of origin for each CD, and handling potential issues that might arise from shipping to the USA once further restrictions are put in place.
In my experience with media, outside of expensive and out-of-print collectible titles, my experience is that it's difficult for a Canadian seller to get a high volume of sales to the USA while also making a reasonable profit for their time. USA sellers have media mail, and there are also large firms like Decluttr that leverage their efficiency to buy and sell pre-owned media for dirt cheap. So for every 10 cheap common titles sold to Canada, I find there might be 1 sold to the USA.
Your experience might be different, but if your volume of sales of cheaper CDs or DVDs to the USA are similar to mine, I think it makes more sense to just close up sales to the USA in a doomsday scenario where they follow through with the removal of the de minimis (as is currently planned).
