cbtmintimeout should have a lower maximum
Wanoskarnet in #tor suggests that the INT32_MAX maximum for cbtmintimeout is ridiculously high. If it were ever set to an absurdly high value, then all users who had LearnCircuitBuildTimeout set would break much of the time, while users with LearnCircuitBuildTimeout turned off would break only some of the time.
60 seconds or so seems like a good "maximum minimum."
cbtinitialtimeout also could use more sane cap. wanoskarnet suggests 120 seconds.