For SNFS, my data's not as good; I haven't done as many numbers, and I haven't been so careful in noting which computer I used for the sieving.

But:

Code:

diff lp time/hrs
204.1 29 441.3
208.3 29 767.3
214.9 30 920.7
216.3 30 1031.2
222.0 30 2459.8 (sieved both A and R)
227.7 30 3494.9
233.2 31r30a 5623.6
248.9 31 18034.3
250.4 31/3r 25997.8 (15e)
285.1 33/3r 166625.8 (16e)

so I think I concur that 29/30 is somewhere around 210 and 30/31 somewhere around 230, and everything gets a bit more confusing as you consider using 3 large primes, different LP bounds on the two sides, and the larger-range sievers at the 250-digit level.