roof or upper cab repair

[deer slayer]

for those of you who have done it i have ave a cab imm working on and it has a bad spot on the passenger side by the windsheild its pretty bad and it dosent have hove for the headliner trim and no cargo light and needs drip rail and some under the drip rail on pass side and i have another cab i drilled all the spot welds out at the floor along the back and cut the front to save the pillar
so my question is where would the best place to cut and weld the front post or even go down more but im trying to stay clear of that
so any pics or info would help great
thanks jeff

[mike nutt]

my roof was ruted out around the drip rail ,about 80% around . i had another cab with a really nice roof with serious floor and firewall rust ,so i cut the 4 post on both cabs at the exact same place (measure, measure,measure and then measure again).then weld the new roof in place.