I think HochHom is the closest thing we have so far, and the canon examply might even be quite clear and maybe even more useful than we thought:

"most of the 23rd century"
{vatlh DIS poH 23 HochHom}
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Although I'm not sure if that can be applied to a not-fixed time period.

The difference here is that a vatlh DIS poH is a time period, whereas wa' ben is a point in time, not a period. wa' ben might refer to a whole year if you're pointing to it in a vague way, but it still represents a point where each year is just one point. I'm not sure it makes sense to say most of a point in time.

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SuStel
http://trimboli.name