It doesn't sound to me like PHI would be good value for you.
Australia's PHI system is heavily regulated, and your premiums *will not* be related to the amount of private health care you would be expected to require.
All Australian adults, regardless of age, health or gender, face the same basic premium for private health insurance. Premiums are then adjusted for income & age . The choice to have equal premiums is a statement of social values, and hugely redistributive, from younger & healthier enrollees to those who are older or sicker.
One of the (equity based) decisions made in the US Affordable Care act was to limit age based differences in insurance premiums to a 3:1 ratio, which underestimates the actual differences in health expenditures. In Australia, that ratio is 1:1, or less, since seniors receive a discount.
On the basis of probabilities, this means that private health insurance is a very poor deal for healthy people in their 20's or 30's, and a very, very, very good deal for those in their 60's, 70's and 80's. Australia's PHI system thus has a number of regulations which encourage, or effectively force, younger citizens to take out health insurance in order to subsidize older enrollees.
The most obvious of these is the medicare levy surcharge which you must pay if you make >(approximately) $85K as a individual or $150K as a family. For most above these income levels, it's cheaper to buy the basic insurance than to pay the surcharge. This is what I refer to when I say younger taxpayers are 'forced' to take insurance.
Secondly, you've alluded to the "Lifetime Health Cover" program, which adds a surcharge to the basic hospital rate for every year you're over 31 and you don't purchase insurance. This incentivizes younger taxpayer to buy insurance, and discourages people from jumping in and out of the system when they know that they'll need care.
You could think of buying insurance as an 'investment', which (assuming that you continue to buy insurance every year) pays you:
2% (after tax) interest/year, increasing at the rate of PHI inflation
On the plus side, that's a guaranteed return that's close to term deposits (after tax), and you get insurance. On the other hand, you have to spend money every year to 'save' this money, and it's a worse deal that the dividend yield on most broad ASX index funds (which also offer opportunities for growth).
Since you don't qualify for the medicare levy surcharge, you would receive a discount on your insurance premiums. However, I think you should consider the circumstances under which you'd actually want to access private care. Unlike in many countries, most acute care and emergency care in Australia is in public hospitals, and you may find that you wouldn't want to 'buy' private care even with insurance, after consideration of the copayments and deductibles.