By "old original" do you mean a black powder rifle? Or is it an older rifle from the smokeless era? They can be two very different things.
I checked the data in the Lyman cast bullet handbook and it says it's for modern smokeless firearms in good condition and not for use with older firearms meant for black powder. That can just be a liability thing though, who knows.
Even if the peak pressure is the same, the pressure curve is very different. There are anecdotes all over about "similar pressure" smokeless loads blowing up black powder cartridge rifles. I don't know how common it truly is but I would stick with black powder or a black powder substitute if the rifle wasn't designed for smokeless.
ADI branded powders aren't very common in Canada so not many will likely have experience with them. I know they do make a bunch of powders for Hodgdon so the US/Hodgdon names would be more common.
Based on a powder equivalency chart on the ADI website:
ADI2205 is within 5% of H4227, IMR4227, H110, W296, and AA1680
ADI2207 is within 5% of H4198, IMR4198, W680, and Reloader7
Where those are within 5% is unknown. Some might be 5% above, some 5% below, and maybe some are right on in terms of burn rate.
The data for the close powders might show where they are with respect to that 5%.
IMR4227 and AA1680 are supposed to be within 5% of ADI2205 but the loads for a 115gr bullets are:
IMR4227 - 7.8 to 9.7 gr producing 972 to 1171 fps
AA1680 - 11 to 13 gr producing 1083 to 1332 fps
They are quite different in load and velocity while producing similar pressures (both maxes are at the max of 16,000 CUP for this cartridge).
Similarly, for the ADI2207 equivalents:
IMR4198 - 10 to 12.4gr producing 1019 to 1272 fps
Reloder 7 - 12.4 to 15.5 gr producing 1038 to 1406 fps
In this case the velocities are closer but the loads are similarly different.
All the data I just listed is for powders that are safe to reduce so I suppose the lower load could be used and reduced a further 10% just to be safe.
According to some Australians I found on another forum:
AR2205 = H4227
AR2207 = H4198
They make these powders for Hodgdon and those are the ADI and Hodgdon names for the exact same powders. I assume ADI = AR?
My manual only lists the IMR powders (made in Canada usually) and not the H powders. They are close but slightly different.
I've swapped IMR and H 4198 at starting loads before without issue so that is a possibility if you use AR2207. The H and IMR powders are quite close in the case of 4198 specifically. IMR4198 is slightly hotter based on load data, H4198 is slightly hotter based on the burn rate chart. Starting loads always seem to be within 10%. You could use the IMR4198 data and reduce it by 10% and use AR2207 since it's supposed to be H4198.
Work up the load, check velocities, all that.
IMR and H 4227 are beside each other on the burn rate chart but I don't know how different they actually are as I haven't used either. Being beside each other just means there isn't a powder in between; it doesn't tell you how close they are.
-----------------------------------------
If it's a black powder era rifle not designed for smokeless, I'd stick to black powder personally, though I don't know what's available in Australia. In Canada we use Goex from the US but I've wanted to try Swiss Schuetzen black powder but I've never managed to find any in Canada. A BPCR shooter once told me it's not approved for importation because no one as ever applied for it to be. Licenses for the import of smokeless powder is difficult enough and not many want to deal with real black powder and it's even tighter regulations. I'm sure there are some black powder substitutes that could work as well.
----------------------------------------
Figuring out the bullet is easy at least. I'd slug the bore and find what the groove diameter is. Load up the heaviest cast bullets you can find. Data seems limited to 90-115gr bullets. There is some data for 117gr on loaddata.com but I'm not a member so can't see the powder weights. It uses SR-4759 (an IMR powder previously made in Canada) which is discontinued by Hodgdon so it may be moot.