Something to think about is how tall the stand will be will determine how many 2x4’s you will need to support your stand. The shorter the upright 2x4 the more weight it can hold if mounted correctly to another board, solid surface, etc… 2- 2x4’s on all 4 corners in an L shape would support your tank and instead of putting a 2x4 in the middle of the front and back I would put 45degree corner bracings on each of the 4 legs for access to a sump incase you use one. Stand could be built under $150 even at today’s crazy prices on wood. Standard pine would support the weight. And oh btw, most 2x4 built stands for tanks are over built anyways so don’t worry if the stand can hold the weight but rather worry and take great care to make it level by it being squarely built. I build all my stands out of 2x4s. Paint or water seal the would for stands that’ll last generations