Yes, you adjust the heat and try to do it in ever smaller increments. I don't use the high setting either but take it up a little slower. Big pressure swings can cause liquid to leak from the jars. My stovetop dials go from 1 to 9, with 9 high. I put it on 7 to get it close to pressure and adjust from there.
My required pressure, adjusted for elevation, is 11 pounds, so I aim for 12 to 12-1/2 pounds. You never want it to go below the minimum pressure and the pressure guage may not be calibrated just right. Your county extension office can probably tell you where you can get the guage calibrated if you wish.
You probably know about the elevation adjustment but I'll go through it anyway. Some guides say to use 10 pounds pressure below 1000 feet elevation and 15 pounds between 1000 and 5000 feet, then 20 pounds over 5000 feet. I think this is so you can use the weights. Others say to go up 1 pound for every 1000 feet above 1000. So up to 1000 feet, use 10 pounds. Between 1001 and 2000 feet, use 11 pounds. Between 2001 and 3000 feet use 12 pounds.
When the pressure gets to about 10 pounds, I start turning it down, maybe to 5 or 6 pounds, so the pressure increases more slowly. I often have to take it down to 3 to stop the pressure increase once it gets to 12-1/2 pounds. Then I may take it back up to 4 or 5 to start the pressure back up once it drops to 12 pounds.
My 30 quart pressure canner has a line inside that shows the minimum allowable water level. I find if I put another two or three pints of water above that minimum line, the pressure is more stable during canning, but it does take a little longer to heat up.
