Is the car standing on its wheels in that pic?

It would look about right if you peeled the existing rubber mount off of it's metal backplate
It's a bit hard to see, is the top flat?
The upper rubber mount is actually a cup kind of thing so it might fit over the top of the new bushing

It is there in the EPC but it's not obvious

If you look HERE where I stripped the rear subframe there's some shots of the main mounting points with

and without

the washers

part number is
52272-20030 STOPPER, REAR SUSPENSION MEMBER, UPPER

Unfortunately I don't have a picture of the underside to show. It has a stup in the centre which slides over the metal insert in the centre of the standard subframe bushing, then a gap then a ring of rubber which contacts the circular part of the subframe itself

To be honest I doubt if it matters if you remove that washer and use Marios bushings directly against the chassis. The difference will not be very large and you'll only lower the rear (the correct way without buggering roll centres) by 5 or 6 mm

Here's a quick artists impression of what I think you have

I guess you might have to get some spacers made up to suit

To me the rubber looks the same size as the bushing

To me the rubber looks the same size as the bushing

The rubber has a metal backing plate attached though (this is what presses against the chassis) and I think it's this that makes the difference in the thickness

I think you'll need to make up a metal spacer to replicate that so that Marios bush + spacer is the same thickness as the stock rubber bush on its backplate