In response to the comment above...
since the gemination comes from the く in ひゃく, ひゃっ is more sensible than ひゃッ
I can add the following sentence found here
I was relieved when the long vacation came, and when it was nearing the end, it was hard to think that school would start again.
in which we see the following vocabulary item with two different gemination orthographies, according to Jim Breen's wwwjdic:
ホッとした from : ほっと(P); ホッと(P); ホっと (adv,vs) (1) (on-mim) with a feeling of relief; with a sigh of relief; (adv) (2) (on-mim) deeply (sigh)
In light of this example, it consequently appears hard to justify the statement that "gemination comes from" a word, or that any particular orthography is "more sensible." Perhaps responses should be based on objectifiable information, such as frequency of a word's or a spelling's occurrence or at least percentages of their acceptability as determined by polls.