I’m making a dress with very heavy embroidery around the collar. However, I’m using tropical weight wool so I’ll beed some serious support. Currently the plan is to underline throughout the whole garment and then also interface where the heavy embroidery will be. Underlining fabric will probably either be a cotton muslin or a broadcloth and interfacing fabric will probably also be a muslin/broadcloth. I’m not sure how to do both underlining and interfacing together.

I saw a recommendation to do fabric interfacing  the same way you would an underlining: where you sew the two fabric pieces (interfacing and fashion fabrics) together within the seam allowance and then treat the two pieces as one piece as you begin to construct the garment. Sounds good to me, but if I’m doing that for both the underlining and the interfacing fabrics…. doesn’t really make sense. And wouldn’t the seams get quite bulky? 

Also, wouldn’t I want the interfacing to be the closest to my fashion fabric (tropical wool) since it will be giving the fashion fabric support with the embroidery? 

But! The resource I found said that I should underline first and then interface!?

I attached a pic of what my inspiration is. Lots of attached trim. Please help! 

 (Also I would like to say that I’m not interested in using fusible interfacing…however if you would like to try and convince me be my guest)

Interfacing on underlining or fashion fabric?