About the materials used by me:
I use the same Aluminium alloy known as 'Bright Aluminium', that other ring providers use as well - AlMg5 (also known as ER-5356). But I use more often AlMg4.5Mn (ER-5183), AlMg4.5MnZr (ER-5087) and AlMg5Mn (ER-5556), that I prefer over 'standard BA', as rings made from are a bit tougher and harder, and so have slight stability advantages, especially when higher ARs are used - and hold their polish shine longer. All these alloys look similar, so mixing can be done most times without any problem. I do not list the wire type of a particular ring batch here, but note it on the storage bags - and you're given the info beforehand, if you ask for.
My Bronze is also not the standard Tin Bronze - so my stuff DOES differ from standard material. It is so called Aluminium Bronze CuAl8, a seawater resistant Copper-Aluminium alloy with a more brass-like look, much similar to 'Nordic Gold'. Thus its color and ageing characteristics is similar to the 10-50 EuroCent or 1 and 2 AUD coins. As this particular Bronze type is a tough stuff to work with (comparable in behaviour to Grade 5 Titanium, so be warned that this is nothing for faint-hearted maillers) I coil and cut it mostly on demand or personal need, and so my ring stock will remain relatively small - but as told, material can be produced anytime, if there's need for.
Recently I introduced another type of Bronze - seeking for a Bronze that would behave as far as possible like Copper, but would be harder, I discovered a low-alloyed Bronze, that is Copper with just 0.5 to 1% of tin added, and perfectly fulfills the requirements I had. Note that this Bronze is also UNLIKE the normally used CuSn6 or CuSn5P Bronze, that most other suppliers offer - due to the fact that it has so little additional stuff added to else pure Copper, it has even the tarnish behavior of pure Cu, just has the stability to be useable also in higher ARs or thinner wire.
Last but not least, I use the Stainless Steel alloys ER307, ER308, ER309, ER316 - and chose the alloys that suit the needs best, in my opinion. While not listed on the web, sales package labeling will give Info on the used alloys, for the interested mailler.