Hey Jim,
Thought about doing the same and came up with a couple of options-
The EMG 35P, an active P-style split coil pickup for 5 string basses with narrow spacing, will fit in the 3.5 x 1.5 inch cavities of the XT-25. Just make sure that the current pickup rings sit inside the cavities so you don’t have exposed screw holes when you remove the rings to accommodate the new pickups.
Also would recommend giving EMG tech support a call with your string spacing at bridge and neck pickup positions.
https://www.emgpickups.com/bass/extended-series/35p-config.html
Btw, any of the EMG 35 soapbar series will fit in those cavities, including single coil J and standard humbucker configurations. You might want to try a P/J combination like on a Spector—. just make sure that the string spacing is compatible.
You might contact Mike ‘Smitty’ Smyth of MJS Custom Pickups out of Ontario Canada. He provided replacements for odd-sized pickups in my 1985 Gibson Explorer bass and a 1985 Aria Pro II ZZB Deluxe explorer style bass. In case of the former, he also provided a vendor who made custom brass pickup rings for me.
Fun fact is he made the P90’s for the Gibson Tony Iommi SG Special guitar.
Just give him the dimensions of the original pickups along with the low to high string spacing measurements at the bridge and neck pickups.
https://www.mjscustompickups.com
Cheers,
James
