Petrovitch wrote:... Can you correct this because I'm certain it's gonna be off ... olim videri bona idea
Well, first of all we can’t translate this phrase into plain classical Latin without stating precisely the meaning of the English expression ‘a good idea’.
1. The Latin word ‘
idea’ means nothing but Plato’s idea, i.e. his concept of a transcendent universal archetype. That’s why I suppose you can’t use this special word to translate “a (good) idea’.
2. But if ‘idea’ means ‘thought’ or something like that you should make use of the Latin words ‘
cogitatio’ (thought; idea, notion, plan, design, project) or ‘
notio’ (idea, conception, notion).
3. good] in this context: ‘
commodus’ (suitable, convenient, commodious).
For further information cf.
Lewis&Short.
The translation “olim videri bona idea” is - sad to say - both grammatically and stylistically incorrect.
The result is as follows:
“It seemed like a good idea at the time” ---->
Haec illo tempore videbatur quaedam esse cogitatio commoda. 
