I'm no computer savvy expert so I brought my unit to a friend who is to do the updating. HE found it easy, FWIW! He just followed the directions in the owners manual. The one trick was I had to buy a MIDI cable (at least I think that's what it was) to do it. It was cheap & I ordered on-line.
My take on the best Jerry lead tone - and I tried everything - is the Classic Distortion model. This is based on a Pro Co Rat. Do not
use the Screamer (obvious what that's based on!) for Jerry though I keep one on my main scene for when I cover other stuff. Set the drive way down, the output way up, and season the rest to taste and you won't believe how sweet it sounds (nothing like the nasty Rat tones cranking the drive up gets you).
This pic is outdated - I've since lowered the bass and slightly raised the treble (not too high - it can get harsh) - but it can get you started.
"For me, I think the only danger is being too much in love with guitar playing. The music is the most important thing, and the guitar is only the instrument." Jerry Garcia