This is another example of how the Players Guide can help you.
Next time you talk to her, simply select the item you want to use as the Appearance, and the item you want to use as the Stats. Click Create and you'll have a whole new outfit with the look and stats you want combined into one.
Important things to note about the Seamstress' process: ->Both items will be removed from your backpack and replaced with the new item ->The name of the item will be transferred from the Stats item, along with the bonuses ->The bonuses of the appearance item will completely disappear, and be overwritten by the bonuses of the stats item, with the exception of No Trade flags. Those will persist to the final item. ->Once the transaction is complete, and you've purchased the item, it cannot be undone! ->This process costs Crowns.
If you want the prize, you have to build the ladder rung by rung. There are no shortcuts.
Also, be very sure that you have the correct item for stats and the correct item for appearance. If you get them backwards, you can end up with an item that not only doesn't look like you want it to, but also has no stats.