Take this for what it's worth. I've only been brewing for 11 months and have 25, 5g batches under my belt. Switched from BIAB to the Spike basket with propane. I have 7 spike basket batches complete. Each batch I've increased my efficiency. First batch was awful at 62% but yesterday's batch was 78% without any effort trying to 'press' the grains for those final drippings or volume. I have started using enzymes. I do a fresh water sparge with ~170 degree water to arrive to the expected pre-boil wort volume. Normally about a gallon to a gallon and a half of sparge water.
Keg King 3-Roller Grain mill. One pass. I don't have a gauge, but estimate based on the Keg King dial somewhere around .035. (One credit card (.0299") will slip in without touching rollers, two credit cards (.05984") need to be 'forced' between.
I have modified my pump recirculation by placing a 3-way valve on my whrilpool TC. Therefore, I am returning wort over the grains but also underneath the basket simultaneously. The flow under the basket, helps stir up and remove a majority of grains that do slip through the baskets false bottom. If I ever do go electric, this supposedly will help me not to scorch an element. (First couple of batches without this modification resulted in close to cup of grains pulled from the wort through a kitchen chinois. (See below))
PROCESS
Mash water to strike temperature with recirculating pump on. Revert pump to under the basket as I dough-in, verify I have no dough balls, let it sit for 10 minutes. After 10 minutes, I do a quick temperature check and have found there is a significant temperature difference between the center of the grain bed and the walls. (I do keep propane low flame lit during mash.) perform a quick stir trying NOT to scrape the bottom of the basket. Temperature check, start ultra slow recirculation, lid and leave it alone for 15 minutes. I'll take a peak around the 25m mark, check flow and for stuck mash. If it's a slow/stuck mash, I'll perform a quick stir. Lid it and leave it be.
Been performing iodine conversion tests around 45 minutes with completion results.
Hoist basket above wort level to continue vorlauf. Modify recirculation flow rate to only flow over grain create a situation where I do NOT have a layer of wort on top of grain bed. I then further lift the basket so I can get a paddle in to stir the wort. Stiring the wort, while the basket is lifted and still recirculating assists in removing much of the grain that may have passed through the false bottom. (Not all, just most).
Once I've vorlaufed and feel my wort is a clear/clean as possible. Pump re-routed to whirlpool only. Raise the basket, well above kettle allow it to continue to drip into kettle. At this point I'll sparge. I'll remove my basket supply hose and run that through a kitchen chinois for a few minutes, again while stirring the wort. This results in about a <1/4 cup of grain being removed and what I believe is as 'clean' wort as possible. (This process is not for the LODO brewers out there).
I leave the basket hanging for those final dripping over the kettle until the final 15 minutes of the boil, it's removed as I begin the sterilization of the chiller, pump, hoses, etc.