You should select your exact phone in the list, and if it isn't present then select Other CDMA Phone.
Picking "similar" phones means you are experimenting and could end up with problems such as your phone locking up with a worst case of it becoming completely inoperable. Different models from the same manufacturer usually have gratuitous differences. Note that in some cases manufacturers ship a phone with the same model number to different carriers, but internally they are very different. If there is a carrier listed, only select the model if your carrier is listed with the model.
The best action to take is to get your phone supported. You either need to do this on the developer group which requires some developer/technical skills, or get us a phone.
Phones the developers have
Loaning a phone
When will you support my phone
BitPim Online Help built 17 January 2010