If I were serious about genealogy I wouldn’t count on anything online or at LDS. Just in the USA mid-Atlantic states alone, some lines are hard to establish as the Union forces had no problem burning down courthouses that contained vital records. But we’re supposed to believe that we can trace back 500 years to some royalty? I prefer to say I come from a long line of Irish peasants.
They sent missions to Scotland (in the 60’s, I believe) and they microfilmed all of the church records. It is copies of these records I am looking at, not some computer generated lists.
If you have a church location, Kirkoswald in my case, the birth and marriage records let you go back to the time when the Catholic records got destroyed. People were much less mobile then, so searching adjacent parishes usually will pick up a lost trail.
There is nothing better than looking at copies of the original hand written records.