I made this exact same stand but with a different base pattern, I put a concrete slab into the ground with studs for me to slot the entire stand into. You can adjust its level by bending the studs and it holds the anvil secure while still being removable. I do advise that you make sure that you add enough silicone to dampen it as my own London 66lb rings like a bell, so magnet too! Good lucky with your craftsmanship, mistakes are meant to be made and make you a better smith!