> my letters are either mischaped or not of the same height . . .
Another suggestion would be to use two parallel lines for writing *between* to
help keep the letters the same height. You could draw lightly on the item with
something erasable like pencil or chalk, or use two pieces of tape, ***
bands, etc. to form the lines.
Another way might be to draw the size and shape of lettering (or whatever) you
want on a piece of paper, then lay a piece of patty paper or waxed paper on top
of it. Create the lettering by tracing over the drawn sample with the clay
snakes. Then either lay the xmas ornament on the clay writing, rolling it over
to pick up all the lettering, or press the writing down a bit then pick up the
waxed paper and lay it with the lettering where you want it to be on the
ornament (oops, guess this way would require the writing to be backwards--in
that case, write with dark ink then trace through on the back side of the
paper, or write on waxed paper or a bit of transparency sheet, etc., then turn
over before tracing).