Every seder I've ever been to has used ground horseradish (like this) for maror, and "dipping" it in the charoset ends up being implemented as putting both maror and charoset on a piece of matzah and eating that. In reviewing the haggadah today, though, it struck me that this takes away from the symbol of the Hillel sandwich that follows, where we combine maror and matzah quite intentionally. So I'm looking for a better way to achieve "dipping". What do most people do? Combine them on a plate (no dipping but no matzah)? Use unground horseradish root (so you have something solid that you can actually dip)? Something else?
The Chabad custom (Sefer Haminhagim Chabad, Haggada im Likkutey Tammim Uminhagim, see also Aruch Hashulchan 473:14) is to use a combination of ground horseradish and Romaine lettuce. We put the ground horseradish inside the lettuce and dip that into the charoses. Shulchan Aruch (473:5) rules that one may combine the different types of Maror, and this custom has the additional advantage of including Romaine lettuce, which Shulchan Aruch considers to be the most preferable type of Maror.
We use unground horseradish. If you can't handle the gases in it, let it sit out for a few hours. Or wrap it in foil right after cutting for the full effect.
We also use romain lettuce bases (not the leaf, the base of the plant) for those who don't want the horseradish (or as a supplement for those who can't eat a ke-zait of it).