What's the recommended XCode to build PPC/Tiger binaries?

I have an older PowerPC iMac G4 running 10.4 Tiger for which I want to develop an application. I do have a much never Intel Mac Pro currently running 10.8 (and I still have 10.6 and 10.7 installation DVDs) which I could use as the machine to write the code.

I've never done anything with XCode (C# developer by trade), so I'm looking for the path of least resistance/configuration requirement:

Run XCode 2.5 on the PPC Mac running 10.4 - SLOW!
Run XCode 4/5 on my Intel Mac running 10.8 - Can I compile for 10.4/PPC without spending a week setting compiler parameters that I don't understand?
Install 10.6 on my Mac and run XCode 3.2.6 - a lot of extra setup work and an outdated XCode version
Use Xamarin Studio - doesn't do PPC?

The App eventually needs to run on PPC, Intel and iOS, although I'm fine with having separate projects and only a single shared code base.

Solution

If this were me, I'd buy an external drive, install a clean copy of MacOS 10.6 on that and then Xcode 3.2.6, which is the last version of Xcode that officially supports PPC development.

You then set your "MINIMUM_DEPLOYMENT_TARGET" for your project to 10.4. You'll also set the supported architectures to i386 & ppc.

The more interesting challenge will be to try to get the same project to build both iOS & Macintosh targets.