Hi Joshua;
1. Not critical- should be 1" to 1.5"
2. No sealant needed if tubes fit tight-check for leaks after turning on water pump/cooler.
3. No need to use provided outlets
4. Water pump, laser, then exhaust and air at start of job
Good Luck
Best Regards,
George
Laserarts
*twin 80 watt Shenhui 1280
*60 watt Laserpro Mercury -42ips
*(2) 30 watt Laserpro Venus-42 ips
*whole bunch of woodworking/metalworking machines
*128 screwdrivers (all needed)
*wonderful wife (1st) of 53 years who allows me to collect screwdrivers