Limiting rear derailleur travel, eliminate smallest cog?

I was lucky enough to have received a Vector S power meter (single pedal power reading that is doubled) early for Christmas and have been riding with it on the trainer for the last month or so.  I know my left leg is weaker than my right due to a hamstring injury I've been recovering from for too many months, have read many posts that discuss the pros and cons of a single leg PM system and paid special attention to the discussion of each leg (especially if one is weaker) tiring at different rates and having a significant impact on the power you see.  This last point I've come to believe in as I've been using the Vector S over the last month.

I looked into getting the right side pedal as an upgrade to make it a R/L power meter system.  Unfortunately, on the right side it requires a clearance of 5 mm between the crank arm and chain when on the largest chainring and smallest cog in the rear.  Mine measures only 3 mm so that is a problem.  I found that I can adjust my derailleur travel such that it will prevent the chain from dropping onto the smallest cog and thus providing the necessary 5 mm clearance.  I'm wondering if there is any downside to this (other than losing the smallest cog which I'm not strong enough to really get much use out of) or mechanical issues it could cause.  Seems like a simple fix, but worried that "If it seems too good to be true, it probably is."