Mark Allen Bradley did make 100 meg 1/4 w P# CB1075 ?? I picked a large number of these and just series them for the exact same thing. not pretty but effective and they were cheap when bought in quantities of a hundred long ago. That with the additional of the digikey 1000 meg, makes a good set of adjustments. Still not the greatest thing for 4G. If I get real desperate, I'll parallel with a good quality high value resistor to get the value under and then series it with a small value fixed &/or pot. Some of my precision dividers have quite a bit of tweaks inside, but they are dead nuts on. To get the neg ohms, Two ways I've used: Bringing out an extra lead from the other side of the switch, for 4-wire ohms, will sometimes do it. The other way that works, is to add a small resistance to make it a nice constant extra 0.10 Ohms (One LS dial setting) high on all ranges and move the dial 1 count on the low order switch (and add an '11'). ws