Unlike side mounted drawer slides, the critical dimension for the under mount slide is the distance from the inside of the cabinet to the inside of the drawer box (slide offset). Many slide manufacturers give you this measurement and the most common size is 21mm (27/32"). You must deduct this measurement from your inside cabinet width for both sides. You also need to add the thickness of the drawer side material for both sides.
Our standard drawer heights and standard drawer material information can be found here.
Our standard inset is 13mm (1/2"). This comes from a dimension for standard under mount slides which usually require a dimension between 12mm (15/32") and 15mm (19/32"). It also allows us to hide the bottom groove nicely inside the dovetails for our standard height drawers.
In our opinion, a two piece door is a better product compared to the traditional method of pocketing or machining out the center panels. Our method produces doors that you will find easier to finish, are less prone to warping, and provide a more stable end product. The slightly higher production cost of this superior product will be easily recovered through your saving in finishing costs.