My 1:12 .300 saum shoots the 180 accubonds very well. That is the longest bullet i have tried but i would have zero qualms about shooting a 200gr partition in that barrel - wouldnt think twice about it. I might think twice about a 200gr accubond
I could be wrong on this but i think barnes recommends a 1:11 for the tsx/ttsx 180s and 1:10 for the heavier ones
IMO people around here tend to recommend a tighter twist than you need, though they are probably right when they point out there is little downside to more twist (within reason)
