Yeah Al, the 11018 rod will make a pretty tough yet machinable edge, I haven`t ever used 11016 so I don`t know about that. When you said "You may ,in fact,get a bit harder surface by using the 7018,or in fact a T-1 type 11016 or 11018,......" didn`t you mean more durable instead of harder?
I have used a hardface rod, Eutetctic 4004, that would flow out to a fairly thin surface layer that was put down over a more ductile layer of 7018 or their own brand underlayment. It works very well and it`s not particularly hard to apply but it goes down hot, about 165 amps DC for 1/8 rod on a machine(Lincoln Square Wave) that normally runs about 115 amps for a good hot 1/8 7018.
One thing to remember is that rods like 7018 and 11018 are low hydrogen or "lo hi" rods, they need to be kept dry in storage, which normally means an oven, to achieve the capabilities that they were designed for. Xray quality welds require that the rod be maintained in an oven as soon as the can is opened, but for farm or less critical welding, the rod can be reconditioned by placing a thin layer on a cookie sheet in a 400° oven for an hour. You know you`ve got everything right with 7018 when the slag curls off the bead.
Russ