I have an Ibanez RG350EX fairly generic rock / metal guitar, which I bought years ago. I have barely touched it in all the time I have had it as I dislike the bland, brittle, post 80s rock sound. I have several guitars and although I like my Fender Strat and Telecaster, my actual favourite is a cheap Fender Jazzmaster copy with p90 pups because of its warm, singing, early 70s tone when put through my Marshall JCM900 with moderate distortion. I want to have a guitar which I can leave permanently in open tuning, and was seriously considering a Squier Telecaster Custom Vintage II which comes with p90s. However, as I have heard a few reports of quality control / staying in tune issues with this guitar, it occurrted to me that I could recycle the Ibanez which has a locking tremolo and should stay in tune longer. Obviously, I am aware that I cannot turn a modern rock instrument into some vintage blues guitar just by changing the pups, but if I can make it sound relatively easy on the ear, that would be enough. Can I ask if anyone thinks this is plausible? I was thinking of changing the humbuckers to GFS Mean 90s as below:

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Would this work? Also, is it advisable to change the middle pickup as well? Generally I use either the Neck or the Bridge pickup positions on the selector switch on my fake Jazzmaster, but am uncertain on how the Ibanez is wired. I have a modest budget, so I don't want a huge splurge on stuff that is not required.

Thanks in advance to anyone that can help.

The specs of the RG guitar from Ibaneze wiki are below:

Body material:
Neck joint:
Edge III tremolo
Hardware color:
Cosmo Black

Neck type:
Wizard II
Neck material:
3-Piece Maple
Bound Rosewood
24 / Jumbo

PU Config:
Neck PU:
INF3 (Infinity 3)
Mid PU:
INFS3 (Infinity Single 3)
Bridge PU:
INF4 (Infinity 4)
1 Volume / 1 Tone / 5-Way Lever