Don't be hung up too much on centralising the engine. Put your front cvt pulley on.Does it fit that taper?
The front pulley inside edge is static as the outer moves in. On the rear pulley it is the inner edge that moves so you will need to allow enough frame clearance for this.
It is the(fully open) rear pulley that will determine how central your engine sits in the frame
If you measure the front pulley width this will give you an idea of the width required when the rear pulley opens up!
The engine will need to be moved sideways to align the pulleys/belt.
Once you are satisfied that the drive belt is straight and you are happy that the rear pulley will clear the frame you can then go ahead with modifying mountings.frame.
It doesn't matter too much about aligning the chain as you will be using a jack shaft and the rear pulley/sprocket can be moved in/out.
You may have to remove the air filter and move the engine further forward to get the right distance between pulleys eg mine is about 250mm!!
Hope you don't mind me saying but I spent hours just playing around with alignment on mine. I initially destroyed the stand spring when the rear pulley opened up
