Hmm... I would consider myself a pretty good flat iron heat person....
This is what I do... Ends are the most susceptible to heat damage (IMO) and the roots are relatively stronger.. (I have never heard of someone getting heat damage on the roots)... anywho..
Wash/Cowash and DC...
Towel dry (just to squeeze out the water)
Apply leave ins while hair is still relatively wet (not sopping/not almost dry either)
Light handed on the leave ins!!! I like these leave ins for light silky hair..
I spray giovanni vitaprofusion first
I use a dime sized amount of my creamy moisturizer (KBB, Jasmines, GAHL Flat Iron Creme) (I like swing and too much of any creamy will give you weighed down)
Heat Protectant.. (Solitude has me really liking Nexxus; but I also bought some T3 Heat Boost that I have not tried yet)
Airdry/Blowdry (pick your poison)
Hair after you blow dry/air dry it should be light .. not sticky or weighed down.. if so.. you used too much.. try to use natural products for my moisturizers.. less chance of getting a weighed down look.
1/2 dime sized amount of moisturizer on the ends.. (just the ends)
Quality Ceramic Flat Iron (FHI Technique/Platform/Runway)
I use 450. I do one pass.. I don't see what the point is of turning the heat down and then doing 5x.. I ain't got all day..
To get new growth at the roots.... get as close as you can to the roots.. and use tapping motion ... open close.. open close.. (3 or 4x..) your hair will be silky straight at the roots. (A must for me)
When flat ironing the shaft after the tapping movement.. make it one swift movement from top to bottom (turning the flat iron for curls; or just curving it outwards for straight)...
Morrocanoil or another light (LIGHT) oil to finish.. starting from the ends and working the way up.
This is just my regimen.. try it.. maybe it needs tweaks for your hair.. but my ends look pretty good and I flat iron pretty regularly with no breakage.
Good luck!