There are a couple of components to God-Meddled Curse that would be easy to rule on. The extra changes that occur at levels 5,10 and 15 would definitely not be applied to the target of the spell.
The rest is a little more up to interpretation. Personally, I would rule that the normal effect of God-meddled applies, but I would cancel any effect with a roll greater than 10. Most of the effects below 10 are detrimental, and Reduce is most often bad for the target, while Enlarge is most often a benefit. Alternatively, you could rule that you only roll 1d10 on the table, forcing all results to be in the bottom half of the results.
I could also see an argument for just applying any and all effects to the target, or not applying any of the effects to the target, since several of the results are not clearly a benefit or a hindrance, unlike with other Curses.