From what little I know, and trying to answer some of your points in your first post...
1. A 275 tyre its generally considered too wide for an 8.5J wheel.
2. A 265 30 will not be suitably load rated for a T28. (I think you can get away with a 99 for the T28? might be best to check your axel weight plate under the bonnet)
I'm running a 255/40 on 20" 8.5J wheels, but my wheels don't need the spacers so can't really comment on that, time for a professional to step in.