Once you've opted in to making SKULabs the master of inventory for your store, we control inventory levels for all products on that store.
Fortunately, through the listing stock and price rules you can control individual listings using a rule skip in place of the store_default default stock rule.
You can configure a listing's stock rule from the listing's details page. To find all listings associated with an item SKU in SKULabs, open the item's details, then scroll to the listings panel. From there, open each listing then edit it's stock rule to the desired value.
For advanced users looking to opt each listing in individually, you can set your store stock sync rule to skip then override store_default with free for tighter control over which specific listings SKULabs manages inventory for.
This can be done individually for each listing or in bulk by using a Listing Rules CSV on the imports/exports page.