Newbie Question Re Resistors in Tweeter path for Magnepan 20.7

I've tried Mills resistors in values 0.5 and 1.0 in the tweeter path for my new Magnepan 20.7s but I think something in between those values would be better.  I have looked for a Mills resistor in this same series between a value of 0.5 and 1.0 but I don't seem to finding them.  Suggestions?  
There is a lot of info on this subject over at audio circle in the planar section audio asylum may also be a good resource.
Good listening..

   Resistors can be connected in parallel, series or a combination, to reach almost any value you desire:
Uh, .5 and 1 in series will be 1.5, in parallel 0.333.
Neither of which is where he wants to be, which is in between.
Its math, not magic.

Which speaking of math, what he could do since he can't find one in between is calculate what values would together with what he has land him in between. But I am tired running math when the info is right there for the taking on the interweb.

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Put the 1.0 and .5 in series then make a second set just the same.Take the two sets, now 1.5 and 1.5 and put them in parallel to make .75
Another way to do it is put a 8 ohm rheostat parallel with a 1.5 ohm resistor, adjustable to any resistance from 1.26 to 0 ohm.
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