As above - it's all subjective. You can do nothing but try different ratios and see how you get on.

I tried a 14T front and found it a pain - forever changing between 1st and 2nd gear off road and made road riding less enjoyable. I was advised to ride faster off-road, advice that proved good and the answer to dealing with the stock gearing for me.

However, it entirely depends on what your "off-road" is? For forest trails, lanes and sand then stock I find fine. In fact lower gearing is more of a hindrance than a help in sand. For technical stuff though, deep mud, ruts, rocks, river crossings etc, I can well understand why you might go for lower ratios.

Don't know the Simpson, but I'd guess it's more open, sandy/dusty and relatively flat? You're probably not going to (unless you look for it) be doing a lot of walking pace technical stuff?

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