If you're only planning to kill yourself, I don't suppose it matters how you do it - short of euthanasia, of course!
But if you want others to be able to use the same approach, there's plenty of mobs in Oz who'll develop the approach for you legally - at a price, of course.
After all, there's no such thing as a free lunch eh!
But, as the
FTDK says, you need a decent survey of your aerodrome first, so that accurate THR coordinates can be established, with heights related appropriately to the WGS-84 spheroid and the published THR elevations, of course. Were you also aware that these coords can drift over time?
I thought not. The survey needs to be updated periodically.