From what you can see, is the neck evenly bowed from the treble to bass side? As in, one side isn't 'more bowed' than the other? If it looks even, it should be fine. But maybe taking it to a tech for a check-up isn't such a bad idea anyway.
My original concern, which others here have labelled as conjecture, is that the proportional difference in tension caused by tuning what I assume to be a standard gauge string set in the way that you describe could, maybe lead to pronounced, more-than-healthy, uneven bowing ("twisting") across the neck over the period of a year. I realise that people have been using uneven sets for decades, but this is a different case. I also realise that uneven bowing can be normal or desirable, to a certain small extent, for some players. Finally, yes, I realise that a twist usually develops for reasons other than string tension.
All the same, think of the neck on a bass that's been sitting in a pawn shop for a long while with one or two strings (usually, and especially, an outlier) missing. It's more extreme, yes, but it demonstrates the relevance of uneven tension here.
