Add boiling H2O until the temp of the mash is 145. Hold for 35 min. It should be about 7-8 qts. depending on elevation.
The next step is decoction up to 158 for 25 min. It will probably take about 6 of the 16 qts. I boiled it for 5 min.
Mash out @ 165 for 15 min. again using decoction, about 6 qts. boiled for 5 min.
*Or just skip all this shit and do a single infusion @ 152 for 75 min. and a mash out @ 165 for 15 min. Note that you will probably lose some efficiency so you might make some adjustments for that.?!.?