Yorkshire Dave
Western Thunderer
Not much room if one was using two motors and an XL decoder.
As long as you use two low current motors i.e. Canon 1833 as in your Cl.22 there is no need to use a LokSound XL decoder. You can use the LokSound L V4.0 instead which is much cheaper than the XL.
Having a continuous load of 3A on the motor output it makes it suitable for twin motor O scale locomotives and is more than adequate for modern low current motors. It also gives you peace of mind if you are concerned about using the standard HO V4.0 decoder for dual motored locos. ESU's additional information guide for the LokSound L 4.0 is attached and apologies if you have already seen it.
The LokSound L was designed to fill the gap between the HO V4.0 and XL.
As Cliff says above - if you mount the decoder to the body (I would also attach the speaker to the body as well) you will not disturb any lighting (or sound) wiring looms. All you would need is a 4 pin connector from the track and motor to the decoder meaning you only have one loom to fiddle with when attaching the body to the chassis. This is my intention with my P48 GP9 but a tad more difficult as it has a long narrow hood like a Cl.20 rather than a wide body (the latter known as cowl units in the US).
Nice diesel builds . Now a guessing game as to what follows the Cl.22.......?