Brick hotplate top

I intend to build in a Tudor charcoal burner on the left hand wall of the kitchen, using Brian Long's instructions, by and large.  I wanted it to have a brick top, like the hotplate in one of the kitchens at Hampton Court (see photo below).

I'm using a base of balsa wood just to have something to glue the bricks to.  Here's what I've got so far:

These are Houseworks mini bricks, available from most dolls' house stockists.  They're a little too regular for the period, so I'm shaping them as I go.  I'm nipping the bricks with a pair of pliers, which works well, but results in a lot of waste.  I'm sure there's a better way to do it, but I have a couple of packages of little bricks so I'm feeling profligate :)

I'll hand paint them for detail when I'm done.

I have no idea what I'm going to use for grout.  If you have any suggestions, let me know, othewise, stay tuned!