Phone app should work if you can find one that has the "C" weighting and the slow option. Accurate or not won't matter too much as you are simply try to match.. It does need to be within 1 dB, 0.5 dB is of course better.
Or simply dial the subwoofer and surround channels up by 3 dB and see if you still like it. From you original review post, it is possible that you may actually prefer the effects of the sub being a few dB lower than the LCR.
In my experience, Audyssey, even XT32 is not able to integrate bass capable towers such as yours with subwoofers. It gets you in the ball park, but you need to experiment different crossover points to find one that integrates the best, that is, with minimum dips and bumps. For the prime towers, I would start with 80 Hz, and then up, but not down, to prevent them from messing with the sub(s).