Here's an answer from a pilot who has, so far, just managed to avoid having to have a hearing aid shoved into the bottom of a flight bag.
South African Class 1 rules prevail here, no idea about Australian rules.
1. The tinnitus is not a medical consideration per se and if the required standard for a Class 1 can be met with the wearing of a hearing aid then that would satisfy the authority.
2. Hearing is likely to deteriorate in the cockpit environment at a faster rate than were you working in a public library. You should perhaps consider loss of licence insurance although hearing might be excluded from such cover.
3. Airlines do not generally seem to like pilots using their own headsets. Interference between headsets in the cockpit can cause problems of communication. Expect the response to be negative.
I would suggest that you get grasp the nettle firmly in both hands and get yourself an initial Class 1 medical check. I suppose it would cost a couple of hundred dollars but it may lay to rest your concerns, one way or the other.
Alternatively, you could find an AME approved for Private Pilot medicals and do one of those. It seems reasonable to suppose that any half decent AME would know whether your present hearing capabilities would preclude a Class 1.
Here's something from England.
Noise & Communication on the Flt Deck