Timing is the killer of header coating in my experience. Having the spark set too late causes the mix to still be burning inside the header tube and red hot happens fast.

Prime the engine with oil 1st before installing the dist.

If you can use an old dist cap that's drilled to be able to see the #1 terminal inside the cap. Set the motor to TDC on #1 (verify by looking down the #1 spark plug hole to make sure you're not 180 off) and look at the holes in the cap. On a B/RB the rotor turns CCW, so spin the dist till the rotor is just barely contacting the #1 terminal from the CCW direction. Then turn the dist approx 35% CLOCKWISE to advance the timing and lock it down. This way you will never start the motor with the charge burning in the head pipe.

If you don't have a cap to drill, use a marker on the cap for the #1 edge location and marks on the dist body for the rotor edges. Brake clean will remove the marker so you can make changes trying to line up the rotor

Mark the dist base to block in case you have to temporarily retard the spark to get the engine to fire initially. Put the dist right back after it fires.

A point and shoot thermometer is mandatory to watch the head pipe temps. Shut it down if they get above 800F. The break in does not have to be in one 30 minute session. Six 5 minute sessions or ten 3 minute sessions is the same.

Fans are a must imo, same for a timing light to get it exactly at 35 before - immediately, 1st thing.

I'm sure some will poo poo my method and I may not have 100% correctly described it, but I've used it on both TTI and Dougs headers and never burn't the coating nor wiped a cam lobe. (yet, fingers crossed)