I've had some super new bases designed for my use (and yours!). A single FK&P14 base will fit a 10cm grid, or a pair is perfect for a 20cm grid. I like to use a pair of bases for a unit, because it is easy to depict disorder without needing a token. The new FK&P14 bases come in five different depths. You can find them in the shop here.
David Imrie has used the FK&P14 bases for this splendid legion, above. Each unit is on a pair of FK&P14c bases.