After using the same, 2% lanthanted 1/16" tungsten for a reeeeeally long time, it was finally getting a little too short to use any much longer, and so I just grabbed a piece of 1.5% lanthanted 1/16" tungsten that I had handy, laying around. I was surprised that I noticed a definite difference of the 1.5% versus the 2%! The 1.5% has more of a tendency to grow the "protrusions" than the 2%.... especially if you keep welding after an aluminum puddle dip. The 2% seems to handle welding after an aluminum puddle dip much better than the 1.5%. The 1.5% grows fairly large "protrusions" fairly quickly. They don't grow as large or as fast on the 2%. I like the 2% lanthanated better; it keeps it point better. It can put up with a LOT of heat and current too. Both are excellent arc starters (especially if bathed in pure argon... it's pure blissfully easy arc starts.)

By the way, I really like being able to just twist the footpedal current knob from 200A to 100A, and simply shut off the Helium gas valve, and have a setup for welding very delicate, thin parts, and then, just undo those two changes, and have a really powerful setup able to melt very thick parts and good penetration. I have rarely ever changed my tungsten from 1/16" since getting the Helium mix... I'd rather just turn on or off the Helium than bother running higher amps on pure argon and force having to swap out the torch parts to put in a 3/32" tungsten. I think the 2% lanthanated (instead of just 1/5%) may be small, but important part of that equation also (for getting that last bit of possible current and heat out of the 1/16" tungsten tip, without it quickly forming the multiple protrusions.)