The explanation to modify the pickups iron bars is based on the magnetic induction. The iron bars help the windings of the pickups to transport more electrical current, so them let to catch more acoustic waves from the sound generated by the strings. The height of the pickups amplifies the acoustic waves produced by the sound. Those two factors determine how much natural or electrical sounds your guitar, aside the windings, the type of pickup and the iron bars between the windings. If the iron bars are within the windings, more current is allowed, and the guitar will sound more electric. Also, if the pickups are close to the strings, a natural clipping will occurs, due to the amplifying effect also it will up the volume. So, my suggest is to test how much affects these factors in your guitars pickups but first measure the actual height, if something doesn't like you want, you can step back.

This guitar has a noticiable change on volume when a split-coil to humbucker change occurs. There are may comments about this on internet, in my opinion, I think the bridge humbucker has a lower output compared to the neck humbucker. By adjusting the heights to have balanced outputs between both humbuckers, the output when is switched to split coil result affected having less characteristic sound (as intended as a single coil). However, one purpose that I do with this guitar and due the unbalanced outputs because the different features between the split coils and the humbuckers, is to use the bridge humbucker for overdrive and distortions, the split coils for semi-acoustic sounds, both humbuckers for overdriven rhythms and the neck humbucker for soloing and riffs.

Somewhere, somebody said about to use a compressor to balance the humbuckers-single coils outputs. I have a Dyna Comp and yes, it works well to balance the volumes. Maybe a rack compressor could do a better job.

Right now, thinking about changing the all the pickguard with Fat 50s single coils.

Or a mixup between Seymour Duncan micro Humbuckers, texas special and Fat 50s

Break news: The last night I decided to equalize the humbuckers, this is to adjust the magnetic poles and the humbucker height. So, finally, after over 3 years, I got a tone that I love from this guitar without regreting any piece. Probably, I would want a little more height in the tremolo to to bends more naturally, but as it is right now is perfect for me.

Ok, fast explain: moving the height of the magnetic poles produces that less or more electric current flows within the coils. So, the closest the poles, the guitar will sound more electrical, and if the poles in a high position, they will sound "vintage" or less electrical.

You need to calibrate every pool in order to get your desired sound, but there is a trick for an instant vintage fender-ish sound: Maintain the poles from the 3rd and 4th strings higher than the another ones. This will clean the saturation and bring more volume, so your guitar will naturally equalized in high output mids, low saturation. The best way to equalizate the poles is to bring your amp to the desired volume and gain level and activate your pedals, also be turning the screws by some degrees and test the guitar nutil you be comfortable with that sound.

So probably your guitar is super good and its coils are also ok but they just need to be equalized to reach your taste in mind.