I pretty much always press from the back but then I press my seams open. I'll typically do a quick pass over the top after the seams are open.
One of my anti-quilt-police things I do is I iron with both a very hot iron and I use steam. It's how I do things and so I don't have problems with it but I can say my pieces are firmly positioned and don't move around.
When I am preparing my fabric for quilting, I'm a big believer in pre-washing and drying which means iron I must! I really don't like ironing but I feel it is essential to what I consider my successes in quilting. I always iron from the back of the fabric, don't really know why but I think it is something that lingers from my 1970 home ec class... It has saved me a couple of times when I had problems of whatever sort with my irons.
Because I don't like to iron, doing it is a priority when I have a drier full of fabric, the real trick is to get it out at just the right point of almost totally dry, shake it out/store it unwrinkled and iron them just as fast as you can. Then I fold them for cutting which also fits the boxes I use for storage. I don't starch and I keep a spray bottle with water on a fine mist setting.