The different hydrations just refer to how many water molecules are attached to each ion when the structure is crystallized (probably from solution in the manufacturing process). Once you dissolve them in water, they should have the same chemical effect, but the molecular weights are different so you would need to convert the weights in a recipe.
I think most photographic formulas are likely using sodium metaborate tetrahydrate, NaBO2 * 4H2O.
I would want to check that the decahydrate is actually sodium metaborate. If it's sodium borate decahydrate, that could be Borax (Na2B4O7 * 10H2O), which is also an alkali but not an equivalent substitute for sodium metaborate.