The Momento is a raised dye pad. That means that the inked pad protrudes well past the plastic box housing. One way is to ink a large stamp is to place the ink pad facing upwards on a flat surface (table), and then press the stamp on and off the ink pad, until the whole area has touched the surface and become inked. Alternatively lay the large stamp runner side up and then press down the ink pad onto that rubber until you can see that it is all well inked. This is the industry standard way of inking stamps.
Yes. You can pick and mix any selection you wish. Individual waxes can be ordered here: https://encaustic.com/product-category/wax-block-singles/ or o a single sheet containing all colours with the order button at the bottom after you have filled in quantity(ies) per colour(s): https://encaustic.com/shop/easy-wax-block-mixed-ordering/
High quality wax colour blocks. SIZE: approximately: 11mm x 24mm x 42mm weighing 10 to 12 grams [ * 1 5/8″x7/16″x15/16″ weighing just under 1/2 oz.] Formulated to high safety standards using: Beeswax ; Paraffin Wax ; Carnauba Wax ; Micro Crystalline waxes ; Glycerine Palmitate / Stearate ; Pigments – see individual encaustic art wax block colours for unique colour specific information. *contain no resins or gums.