Rollcages and headliners

Headliner and a cage is no problem and looks very nice. Use shields to keep the heat off the headliner if you put the headliner in first. Your choice seems to be decided which is more difficult. Welding a cage in with the headliner in place or placing the headliner with a cage in the way. It would probably be best to get your headliner supplies and see how hard it will be to place it after the fact. Welding with the headliner in place is tedious but doable.