All of our supplies with detail measurements in each listing. As some people like to measured by inches and some by millimeters. 1 inch equal at 25.4mm, while we also thought 1inch at 25mm, that is not exactly same size. So in some of our listing, if the blank size at 25.4mm, we would make a special note.

Except that, all our blank size we listed is for interior size, so 18mm blanks work with our 18mm glass. If you are not sure, just convo me.

Yes, Etsy would automatically calculate the shipping cost once the listing is added into your cart. The shipping of 1st item is the most expensive or heaviest, then the added items are calculated with an added-on shipping cost.

Yes. We offer different discount coupon based on different order amount. If the code is not working during the checkout, pls double check the typing code, for example LUCK80 instead of LUCK 90, no space.
https://www.etsy.com/shop/Bronzemetal?ref=hdr_shop_menu

Also you can contact me directly for large order, I would reserve a listing after agree with the price.

Yes, if the order amount more than USD 150 (include the postage), would upgrade the shipping directly, not include the remote area of DHL. Also you can upgrade shipping with below listing directly:
https://www.etsy.com/listing/208802991/upgrade-to-dhl-or-ems

Would ship within 3 days of receiving your order and payment (except for weekends and holidays, or custom and wholesale orders). If you need your items more quickly, pls choose the option of express, convo me or leave a note after place the order.