I almost think there's no difference to worry about, mag rims are naturally robust, more so than their spoked counterparts which themselves can handle what these engines produce. If you get a mag rim you're set unless you crash and crack it. Don't know where wind resistance means anything since all that can do is slow you down, you'll see more force against the wheel from dumping the clutch or simply making leaning turns than what you see when a engine is forcing you through air. I'd say pick whichever you think looks better, if considering all out strength then cracking an arm on a 10 arm will be less detrimental to the integrity than cracking one on a wheel with only 5 (10% vs 20% of how many arms you have respectively.)