It is a most confusing time to try to learn Crafting. All the skills tended to have the same skill reqs and costs for some time. Now that the big 'adjustments' have started to happen, some of them behave differently. To add to that, a big bottleneck for VR is limitations on the time of coders. So the changes are coming in slowly and the patches and bug fixes take longer than we'd like.
The longstanding rule of thumb - that still applies to much of it - is that T1 needs skill of 1, T2 needs 25, T3 needs 45 and T4 needs 65. Also, T1 schematics cost 1.5 silver, T2 is 4.5s, T3 is ~75s and T4 costs over 1 gold.
Weaponsmithing had the big change that asherium chainmail was removed, bronze chainmail became the T1 metal armor you can make at skill 1 EXCEPT that making some of the parts as well as the bronze bars are in the B.smithing and Smelting skills and still require 25 skill. I don't know how that will be resolved.
'Metal' is always the lowest tier/most common metal you are mixing with a less common or higher tier substance (usually a metal) - the 'precious' one.
I hope some of this helps.