20 Gal. batch

I’m wanting to start a 20 gal. batch. I’m used to doing 5 gal. batches. Any advice on ingredient conversions? Do I just x4 my ingredients, or is it a little trickier than that?

Should be straight forward, times 4.

You don’ have to worry about it until you get into REALLY big batches.

Any reasoning behind the 20 gallon batches? Just curious; more beer is never a good thing but I’ve always liked having variety on hand. Had a friend recently who did fifteen gallons and we used the opportunity to go ahead and test out three different yeast strains on the same wort.