keeing temperature low on Chargriller with SFB

I assume you have done the mods to lower the smoke stack and what not, so here is my take on keeping temps low for jerky.

Light approx. 20 briquets (not lump for this), when they are approx. 80% lit put 10 of them in a nice small neat pile in your firebox (use tongs to stack them). Close your smoker up and watch the temps., add more briquets one or two at a time till you get up to the temp you want. Add your meat, then every 20-30 min. add one unlit briquet to the pile.

The reason for the briquets is they burn very predictably and stable, lump can flare and get hot on you real fast.

For your "smoke" snuggle a small fist sized chunk of flavor wood up against the coal pile once an hour, close enough to smoke, but not to burst into flames.