I made a riser for my 8 X 36" mini BP; I'm 6' 2"
I went the simple route. I cut some 1" X 6" MDF (That fake chipwood stuff) planks and simply made two stacks of them, a total of perhaps 6" front and rear, and placed a piece of galvanized sheet metal on the top layer. Got the mill onto that, and it's worked fine for 15 years. One advantage is that the chipwood compresses and any base casting inaccuracies are absorbed by the wood. The whole thing becomes stable and shake-free after a few days.
It's not perfectly level, but I've never used a level in set-up, and it has not created any inaccuracies at all. The machine produces true right angles.