This mod sounds a little raw, but for a Jap Ho ...
Dismantle bridge, drill screw between studs into wood so you have a triangle "stud-screw-stud" (no, Mark, not what you are thinking, a geometrical, not a love triangle) pointing to the neck. Reassemble bridge, leave screw "out of the wood" enough so its head supports base of bridge and keeps it from tipping forward, you can even elevate it a little in the other direction. Drilling a hole into the bridge that gives you access to the screw head with a screw driver (but not large enough to actually swallow the head - I know how these three innocent and largely technical words I just used will raise a lively discussion here
- in a self-defeating way) makes the bridge tilt adjustable even with the bridge mounted.
It's the tried and trusted principle of the Guild two point bridge where a knurled thumb screw mounted before the two studs did not additionally fasten the bridge, but only stabilized it from dreaded tilt.
Or do what I did on my EB-4: slip two coins underneath the edges of the bridge. Works and you always have a coin handy while playing bass!
Uwe