None of the below are paid promotion, so you can rely on my honest opinion.
AliExpress RGB shifters
When it comes to RGB modding, a common phenomenon you will notice is that the RGB image gets shifted (horizontal shift) to the left slightly. Therefore, you have to make a minor adjustment via service menu to re-center the image horizontally.
While this can be accomplished through the service menu in most CRTs, there are few reasons why you might want to use an external RGB shifter.
- You don't want to shift the composite, s-video image. Service menu shift is typically universal and will impact other inputs
- You can't get into the service menu for your particular set
- Complex RGB shifting methods that requires opening up the CRT
5 in 2 out RGB shifter from AliExpress. It was around $75 USD, incl. shipping.
Okatu RGB shifter
I have also read some decent reviews about the 6 Port RGB Scart/RCA/Component Switch. I have not tried this switch personally to shift RGB images. Please note that there were some users who complained about a slight wobble. This is apparently due to the VPOS shifting. Several had better experience when they had the option to disable the VPOS shifting. Not sure if that is possible with the Okatu switch.