Whatever is comfortable...for the lady is what I prefer.  
It will not

wear sweat pants if that's what you like. If everything goes well they all come off. Just wear your personality and a smile, that's what counts best for me. Of course sometimes when the mood is right I like to remove the ladies garments with my teeth, so be aware.

Cute and casual does it for me. I’ve never made an attire request but I’m still new to this and generally leave it up to the lady to decide how she wishes to present herself. I do like the idea of peeling off the clothing to be surprised by what’s underneath.

Have a real fondness and weakness for sexy lingerie ie La Perla or Agent Provocateur under a dress or blouse and skirt w/ a garter belt and stockings. Along with stilettos. Love to run my hands up a stockinged thigh. Nothing hotter than the lady comes back from the ladies room at dinner and putting her panties in your hand.   Seams and Cuban and French heels are a bonus.

You would look great ..

Darlin, you look hot any way you slice it ..
I think cute and casual can make for a more realistic GFE but lingerie is fine too. More important is the smile, the attitude and the interest in the session

I enjoy lingerie as long as it is not complicated to remove. So much of it can be a bit on the tricky side.  
I am also totally ok with cute casual, as long as it doesn't appear that little to no effort was put into it (yes, I have arrived and wondered, did she forget that I was coming)
Nothing beats panties and a button down shirt though.