Hi,
as you you wrote it is recommended to use separated antenna and keep them as far as you can on the platform. before going to layout, you may try with TI Kit to learn the performance. I strongly recommend you to move to 1831 than 1271. the price and size are more attractive. the WiFi/BT coex is better and you can get up to ~100Mbps in a quiet environment - 11n, 40MHz SISO.
Eran