When I went all-grain about 10 years ago I built a picnic cooler mash tun based on Denny Conn's Cheap-n-Easy design. Initially I added the strike water and stirred in the grains. Now that I have a pump I first add some rice hulls along the torpedo braid and then add the grain, and then transfer the heated strike water to the cooler through the ball valve. . I transfer at a slow/medium rate. I found that if I fill too fast I get more dough balls.
After mashing is complete I use my pump to vourlauf slowly for 10-ish minutes. I use a colander to help diffuse the output flow so it doesn't dig a well into the grain bed. Then I drain the tun through the ball valve to a bucket, that will be carried out to the brew kettle.
Since I don't have a port on the 5 gal (19L) kettle that I use to heat my sparge water I carry the kettle over and pour it into the mash tun for a batch sparge. Sometimes, I transfer the first couple gallons using a large Pyrex measuring cup and then dump the kettle. After stirring in I let it sit for 10 minutes then do a vourlauf and drain to a bucket.
Normally I mash inside but, in the picture below I mashed outdoors because the kitchen was being worked on.
View attachment 33081
Below is the torpedo screen made from the exterior mesh taken from a water supply hose.
View attachment 33082