i do believe quite a few people have been getting pretty good results from using the 1lb setting to roast 1/2 lb (approx. 226g) up to about 350g of greens.
the general consensus that i have noted from most behmor users on the site stick to that with some prefering p3 and some p4 depending on bean type.
not getting to first crack would indicate an inadequate amount of roast time i suppose
using the 1lb setting would solve this
of course you dont have to leave it to cycle all the way through the program and should pull it out as soon as the desired roast level is achieved.
it is difficult to just give you a profile for each bean as well, to each their own really
im sure someone will come along that will be able to provide a higher level of insight