The way things are, there's no way to tell where you can apply a tech until you check the list on the item creation window on all your forms... which is both frustrating and confusing. You have to end up going through your list of forms, checking every single one of them to see whether or not you can technique it with the one(s) you want.
Dragons don't ever run into this issue except on very rare occasions where a tech conflicts with a scale's existing bonus. But bipeds are utterly plagued with this, every technique has its "do's and don'ts" for them with no real discernible pattern. How do you know where you can put a weaving technique? You don't! Just check every piece of equipment's form to see if you can apply it there.
Ideally, we would see something like these example descriptions on all techniques:
Craft: Smelting V
This technique gives the user the ability to create certain objects with an additional +20 to the Smelting trade skill.
This technique can be applied to the following item types: tools, waist armor, hand armor, shoulder armor, leg armor, left-hand containers, necklaces, rings, dragon claws, and dragon scales.
Conflicts with: smelting up
Statistic: Strength V
This technique gives the user the ability to create certain objects with an additional +20 to the Strength statistic.
This technique can be applied to the following item types: weapons, tools, waist armor, head armor, back armor, leg armor, chest armor, forearm armor, shields, left-hand containers, earrings, necklaces, dragon claws, dragon scales.
Conflicts with: strength up
With the above implemented on every technique, it would remove a lot of time and confusion in crafting a full set of something with technique X. You'd know exactly where you can apply the techniques you want and the list of conflicts would tell you that for example, you can't make strength scales with a strength technique before you mistakenly try that.