Clarke gaz tank

[416HL]

I just receive my new gaz tank, and I got some difficulty at the installation.
This is the final result. I am wondering if its normal to have a gap between the seat and the gaz tank?

Maybe I did a mistake?

Thank you.

[416HL]

And...

[HiZ]

Not sure on the tank, Like the mirrior though

[enduro400rider]

on my oversized IMS theres a gap like that i think its normal the oversized ones just dont fit as clean as stock