OK, I don't cook any liquid soap anymore. I find no need. At the most, I melt the coconut oil in the crock pot or microwave. And when the house is over 68 degrees, I don't even do that. BUT, I have trial and errored my recipes to refine them to use nothing but CP for liquid soap. Also, I don't really care if the soap is thin when diluted. That makes a world of difference.
You don't need to boil the water unless you are in a hurry. This is when a crock pot comes in really useful. Just add your hot(or cold) water and turn it on high. Break the paste up into chunks and add it to the water(or the other way around). You will have to learn your dilution rates for each recipe, so be sure to write down how much water it took to dilute so you know for future reference.
Since you chose to use a recipe that I don't know what it turns out like, I can't give you any clue how that soap is going to turn out. You will have to let us know, OK?