Mornin, Tracy. Sounds like the siding install is a little more free form than you expected.
A soon as I saw what he was into I pretty much knew what to expect. I've had to deal with old houses like this several times.
The real problems arise when you have a product like siding that just don't allow much margin for a lot of "free form". You have a 1 1/2" overlap on the row beneath the one you are putting on, but if you try to cheat it too much it just ends up looking like **** which = unhappy homeowner. Inside corners are where you really have to be on. Once you get away from that the differences aren't so obvious
We really need to get this portion of the job done so we can move inside before the cold weather really sets in and start hanging drywall.