roof wall integrity

[rvlh]

I am tasked with completing the construction of a small cabin. My concern is that the front pitch 10/12 and the rear pitch 5/12 of the SaltBox design will stress the opposing walls The cabin is 24ft. by 20ft.The front half is vaulted and the back has a loft. To allow for this the builder has the eight foot front wall vaulting sixteen feet to the ridge. The back wall is a fourteen foot balloon framed wall vaulting approximately ten feet to the ridge. Collar ties are at every other joist (32"oc) and the ties are positioned approximately one-third the way from the top plate of the back wall, allowing for approximately seven foot headroom in the loft. The roof joists are 16" oc with 1X6 purlins supporting a tin roof.
The other elements of construction are fine with attention to detail. Opinions on the integrity of the roof joist framing is appreciated.