Hi Jim,
I have something even much better for you ... 
The MM "Big Al" wiring for your setup ...
A JPJ bass,
1 Volume, 1 Tone,
3x DPDT switch (On/On with 6 lugs)
1, 2 or 3 SWITCHES DOWN =
These PUs are on, wired in parallel mode (if more than 1).
ALL switches UP: The two
Js are wired in SERIES ...
There is no more GERNEAL OFF anymore.
Instead you have SERIES
Js in this position.
For general off, put the volume pot to zero ...
Here is my "Wiring Compendium" with 417 pages at the moment as a 6.35 MB file:
http://161589.homepagemodules.de/t29...-E-Baesse.html
Go to the bottom and click the "Bassschaltungen391.pdf".
Wait until it has loaded and save it onto your harddisk.
This wiring has the number 2.9.15 and is on page 355.
The page is in German, but you will understand that "Masse" means Ground.
A litle bit confusing might be that "u" doesn't mean "up" but "down" (because of the German word "unten").
The "o" is "up" (oben - these words have the same origin).
"Saitenerdung" is "String grounding" ...
With DiMarzio Humbuckers you needn't put grounded copper under the neck J PU. With normal SC
Js it is better ...