The Last Bass Outpost

I finally got the bass wired and set up. I used a 500k pot for the model G.
Only thing that bothers me is the loss in volume when the two pickups are full on together. I know it's a common problem with all two pickup basses, but the loss here is much more than in the J basses i used to have. Does anybody know if it's because there's a big difference between the wiring in the pickups or did i do something wrong?? 

Wow guys, thank's a lot, you're giving me a lot to think about....i guess thats why i've always stucked with one pickup basses.... 

My intention was to dial in the bridge pickup only when i use the Model G in single and try to get a Jazz-a-like tone out of it all. On the bird, in single mode, it sounded more similar to a single coil P than to a J neck pickup, more clanky, nice for sure, just not ......Jazzy
I could try a 250 or 300K pot on the Model G...just to try....

Guy's, i'm moving a Model G from my Fenderbird to an SX jbass.
I had the pickup wired to a DPDT switch to use it in parallel/singel/serie. Now i would do the same on this bass but i'm installing a bridge pickup also, in the hope to archive a J-like sound. I'm not sure of the wiring so if anybody could help me before i get other components i'll be thankfull.
My doubt is that, in the attached wiring diagram, without the second pickup, the hot wire from the Model G goes to the side socket:



while in the other, with two pickups, it goes to the central...:



PS: no tone switch...

It looks like one of those copies you find on the chinese 3bay, like Alixpress.

I've found a US made Ampeg sv15 and an ashdown vs212 elsewhere... i'm mostly open to the 2x12, as i like 12" remembering the Marshall cab, but i can't find much specs on the Ashdown and many people say's a lot of good thing about the sv15 as a stand alone cab.......could i only try the two side by side...

ja, lige bag hjørnet....just around the corner... 

I've heard bad things about the Ampeg 212AV, wouldlove to try one out. I've thought about Avatar too, but i'm in Italy, the shipping from US would kill the deal....and i would be charged 22% extra in taxes.. 

I've also been thinking of a 1x15, but am afraid i would loose something in sound and just be boomy...I know, you need to try the cabs...