Question re: EO's vs. FO's in bath salts and glycerin

[ScentsandMore]

I have a recipe for bath salts and it calls for 12 to 15 drops of essential oil. I only have FO's. Would I use the same amount of FO as it calls for EO's or should I add extra drops of FO's. Also, it calls for glycerin. Is this the same thing as liquid glycerin you can buy at Walgreen’s or Walmart? Thanks.

[CareBear]

I find that most EOs are much stronger than FOs, but it will all depend. Actually I might use 1/3 the EO as the FO...

And yes, glycerine is glycerine.