I've recently upgraded the outter and inner shafts to longer Vortex ones, i have my servo linkage on the second hole for sum outdoor flying.....i recently had a slight blade strike and i wasn't flying fast or hard or made any sudden stick movements for that matter.

I've read where sum people trim the lower blades down to 5.5" and this, coupled with the upgraded shafts, virtually eliminates blade strike....my question is y trim the lower and not the upper blades? Is there sum advantage to doin this and wat is the disadvantage of trimming the upper blades instead?