From the pictures it looks like you have SD P-Rails with the volume pots for each pickup having a push-pull arrangement, though I can't tell from the picture if it's for coil splitting or series/parallel wiring. A good way of getting the most out of a set of P-Rails is to use the
Triple Shot mounting rings. I used them in my H150 Special, and they give you the following options from the two little switches on the ring - humbucker (coils in series). P90 coil, Rail coil. humbucker (coils in parallel). Something to be aware of is that you might have to shorten the pickup lead quite a lot to get it to fit in the pickup cavity. If you use the Triple Shots you can use a regular volume pot.
I found I was using the P90 setting most of the time so I eventually replaced the P-Rails with a set of Phat Cats. I still have the P-Rails, all I need is another guitar to put them in...

. Here's a pic of the H150 Special with the P-Rails and Triple Shots.
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