@Swift There are too many "hidden meaning" deals on the gifts for this stuff in Japan so I'm not sure, I really only remember the significance of giving marshmallows (I don't like you) or hard candies (I like you) on White day. For Valentines though, I think it's pretty much just chocolate in whatever form you want to give it. Some people might not like regular chocolate, so white chocolate might be an acceptable alternative to them. As far as I can remember, the only meanings on this end were attributed to whether they're supposed to be giri (obligation, like thanking them for their help and such), honmei (love), or straight up pity chocolate 'cause you know that poor sad sack ain't getting shit from anyone else (probably best to tell them that it's simply giri).
Also, women are just making up the White day hidden meanings all on their own and the men probably don't know jack shit about them anyway according to basically every manga ever, so that's also something to keep in mind. Maybe if he gives you marshmallows on White day, it's because you told him you like them in some other part of the year where they aren't a goddamn land mine.