The classification is compounded by the fact that there were very likely many hybrids, some that have occurred relatively recently (early 20th century). Some of this is likely due to sharing tunes. The long Scots version here shows some evidence of being a hybrid of TBYS and TRB.

My shorthand system of study/comparison involves designating each stanza in the group a letter and then listing them side by side. With most ballads this throws up interesting patterns, but the laments are much more difficult and patterns are few and far between. Much closer analysis is needed.