Question Centre speaker location

[mcmental]

Quick question folks, I have recently purchased some Dali zensor 3 speakers and a Dali vokul to run with my Yamaha rxv779 as you can see in the picture the zensors are on stands at side of the cabinet, should I use the centre speaker inside cabinet or on top is my question? This is all running with my projector and screen.
Thanks

 

[PSM1]

Given your fronts are so close together I would have not bothered with a centre at all since there is going to be no separation of sound. You have effectively made a soundbar.
Of the 2 options on top is the best but neither is ideal since a speaker is not going to sound its best either inside or on top of a cabinet. On top can be made better by using a foam isolation pad to place the speaker on and bringing it forward so it is proud of the front of the unit. Ideally the centre should be on its own stand or wall mounted using a proper speaker bracket (not a shelf).
I would also look to move the front L/R speakers out much wider than they are to give a decent front soundfield.

 

[mcmental]

Thanks for that, I've left a spare 4foot of cable on each speaker to allow me to get best location/sound.