Youve gotta clear the current beetles in the area, its a type of NM that only spawns if there is an open slot for him.
I ran around for 20 mins killing the beetles as a 11 or 12 PLD and then he popped east of the mountain thats north of the spawn area
mountainmountainmountain pop
op path------------path
mountainmountainmountain
Best help I can give.
I havent realy noticed any additional evasion but the sheild has great defence for low level and is really easy to get so I suggest any pld/war in the dunes should have it.
Edit: paladine, were you at the fanfest in gardena?