It's good to be interested; it's foolhardy to be "dead set" on anything. And your handiness due to familiarity with construction is good for you to have an inclination toward ortho, but those direct skills will likely not matter for matching. Residency programs are built on the foundation that they will teach you to operate, whether you've been working with your hands for 15+ years or not. They do not select candidates based on "this person has a lot of experience working with their hands so it will be easier to teach them," but instead, "this person will make a great surgeon, and they will work extra hard to meet our standards."
Congratulations on your interviews. If you attend a DO school that doesn't have an affiliated ortho residency program, it will be more difficult but not impossible. Like I mentioned earlier, focus on your academics above all else. Apply for a summer research position at the NIH or a similar program. Pick up some away rotations and go above and beyond in your assignments (note: that does not mean brown-nosing the attendings). Just because a school doesn't have resources readily available does not mean that there aren't people there willing to help if you show interest, and it does not mean that you're "screwed" - you might just have to put forth extra effort to explore those options.
In general, I don't think allopathic residency directors have a bias against DO students, at least not in recent years. They may have a bias against certain DO schools, but those tend to be the institutions that are under scrutiny by their accreditors. The case is the same with MD schools. Your class grades and performance on the USMLE will prove your capabilities; it then becomes a matter of how well you mesh with the atmosphere of the program.
Western is a solid program, from what I understand. One of the residents in my allopathic program was from there, and the doctor I talked about in an earlier post (#57) was also a Western graduate. Additionally, the father of one of my close friends was a member of the charter class at Western.