Is it okay if I....

Sodium Lauryl Sulfate is one of the more harsh types of detergent, but it should not hurt your hair that much since you likely condition afterward.  If you want it to be less drying, you can use it diluted.  Sodium laureth sulfate is less harsh, (but I still dilute that too). 

Using heat that much is going to damage your hair over time, and it gets a little harder to keep even natural un-dyed and un-heat treated hair in good form even after bsl just because hair this long is a couple of years old and all the washing takes a toll on it (though of course it also depends on your hair type...coarse will get damaged less easy, fine will get damaged more easily).  I am going to waist length too and I'm getting a lot more splits now that my length is this many years old, even though I don't do those damaging things to it.  You may want to consider not straightening if you can.

I can't use shampoo with SLS because my hair sheds an enormous amount. I use Giovanni 50:50 and dilute it.

You can use an empty small bottle, put some water in, then put an equal amount of shampoo in (this makes it 50/50 or half and half), then roll it slowly to mix it.  Make only what you'll need at a time because you don't want it sitting around diluted.  (I doubt soapy water would grow much in it, but you never know so best to just not let it sit around).  

It will still make suds and clean your hair, and you'll get the benefits of a less dried out scalp, which also is less greasy because the scalp doesn't try to overcompensate for the dryness caused by over concentrated shampoo (which most are).  After you get used to it, you may find you can get away with using only 25% or even 10% shampoo to water...whatever works best for you. 

I use only diluted shampoo now, my scalp has adjusted, and due to it being less greasy I can even go one extra day without washing now, which I could never get my scalp to adjust to before.  Another benefit is you can buy any ol' cheap shampoo because diluted it won't ever be very harsh.

Hey thnx I think I am going to try that too

Hey Dave! you have beautiful hair. Thank you I will try using your method the next time i wash my hair.

what kind of shampoo are u using lola

i love it because it leaves my hair shiny and smooth.

i didn't know that either .  My hair gets greasier faster now that I use HF37.  HF37 leaves my hair silky and smooth at first but the next day it looks real greasy.

I finally bought a small bottle and will try Dave's advice .