Holy cats! You don't need to do a mash at all, so all you need to do is steep for maybe 5-10 minutes while your water is coming up towards the boil. When the temperature hits 150-160 F, keep it there for a couple minutes, then increase the heat and remove the bag as soon as the overall temperature hits about 170 F. Then turn off your heat, add the extract, stir well to dissolve, then boil and brew like normal. No need to dork around for 30-75 minutes if you're not mashing any base malts!! It's just a steep for flavor and color, not to convert starches into sugars. If you had base malt in there, then you'd want to wait for at least 30-40 minutes. 75 minutes would be mega-overkill IMO.