You are 6'4" which is approx. 1.93 metres. Therefore your eye height will be approx. 1.78 metres.
The Manfrotto 055XB Classic tripod, recognised by many photographers as an exceptionally strong and versatile tripod, (available for around £110.00), can, (by removing centre column and using the second supplied tripod head adaptor), go as low as 7cm, and fully extended, as high as 178cm.
Load capacity fully extended is stated as 7Kg.
(NB: The height of whatever tripod head you are using, plus the height of your camera to its eyepiece would need to be added to both of the above stated heights).
By no means the lightest, but in all honesty, it's the best tripod I've used. So if weight isn't an issue, I'd suggest giving it serious consideration.
A typical "all rounder" 3-way head would be something like the Manfrotto 808RC4, which can handle 8kg, and costs around £120.00 This would give you a further 150mm height.
I use an 055XB with a 405geared head, but my photography never needs the extreme height that could be achieved.
So - rather than mess around with the secondary head adaptor, I just sawed off the centre column - leaving me with a very rigid tripod whose legs splay out to within two degrees of horizontal, and which will still give me a maximum working height (to my camera's eyepiece) of approx. 163cm.
Regards,
Mike.