Normal range on my labs has always been 83-344ng/mL and I hover between 250 and 300. Americans statistically have higher IGF-1 levels than most of the world due to high meat diets. Studying the consequences have been all the rage for the past decade with all evidence pointing to elevated cancer risks. The suggestion of stacking with test and tren is first anecdotal and second referring to supraphysiological levels of IGF-1. E
As far as how much peptides increase it? Totally depends on the compound. GHRP/GHRH at 100mcg/100mcg 3x per day shows around 10% increase from baseline IGF-1... though that's not its only benefit. IGF-DES @ 100mcg per day will peak about 15-25 minutes after injection and can raise IGF-1 levels by as much as 100% depending on the person. But it very rapidly declines over the following hours.
Your levels are pretty desirable and are definitely a gift for building mass. Makes cell proliferation much easier than someone that eats well and still has lower levels. However its not equivalent to having teenaged levels of testosterone in your blood for overall anabolic growth... but not much is

.