I removed and reinstalled my headers fairly easy by just removing the radiator bolts and moving it out of the way leaving the hoses connected.
I never used a torque wrench though and just done them up firm, when I removed the bolts originally they were different in their torque settings , guessing they move with the running in of the bike.
1994 GSX750 Katana (Popup)
2005 V-Strom 650 Blue
2016 GSXS1000F Blue