I'm about to start my biggest extraction yet (500g powered bark) and I wanted to confirm some ratios before I potentially ruin another batch. My pervious ones all ended up with emulsion I think from a mix of maybe too high of a PH and over shaking. I am planing on using the STB tek and following ratios from nature boys tutorial on shroomery. It says I should be using ~3000ml of distilled water for this much bark. From my past extraction experience that seems a little high and I'm unsure how much water to use if I do a 1:1 lye/bark ratio if I'm aiming for a PH between 13-14. Could someone with a bit more extraction experience pitch in on this hypothetical situation, thanks.

when I do extraction the ratio is :

1g MHRB to 15ml of water to 1g of lye

so I would use more then 3 litres for 500g of MHRB

15ml of water to one gram powdered MHRB is a good ratio so you are looking at using 7500ml of water. I've only done 100 gram extractions but 1500ml is the perfect amount of water for those. If you have yet to have a successful extraction, I wouldn't start trying to change around the ratios. I would also suggest not extracting all 500 grams at once until you get your technique down. Why not start with 100 grams? The more water you use the less likely you are to have an emulsion as well (you don't get an emulsion from your pH being to high)

You've been getting emulsions because you haven't been using enough water. For 500g of bark you will need at least 7500ml of water, possibly twice that.
For this size extraction, an A/B would suit you a lot better.

I agree that you need more water. Don't worry about the pH being too high

You said you messed up other extractions? A larger extraction isn't going to make an extraction any easier. I say keep with 50g mhrb until you have a successful extraction.