Creating BizTalk Hosts and host instances can be done with scripts. Below is script for creating hosts:
This script will result in following outcome:
Looking at properties it, 32-bit only is checked and others are unchecked. The same behaviour occurs if this script is performed in 64-bit environment and something you might not want.
Script I showed at begin is one I have been provided with by a colleague and useful to create one or more hosts. Key here is MSBTS_HostSetting that has a couple properties like AuthTrusted, HostType, HostTracking, IsDefault and IsHost32BitOnly (there are more). This gave some insight that script can be altered to have a more desirable outcome. I altered the script by adding setting for HostTracking, Isdefault and IsHost32BitOnly.
Running this script gave me a more desirable outcome:
As you can see there is a lot flexibility here as you can alter the script to any possible outcome depending on the situation required. There is also a tool available to create hosts and some explanation (background) that is very useful.