It all depends on how much work you can and are willing to do. I’ve got a 4/s on an extended porch Tony, but it required a custom motor mount top plate and the Tony porch kit isn’t even close to complete so that required a good bit more fabrication. I’m happy with the kart now but it took a LOT of work to make it happen.
I’ve always admired Margay and want to support American manufacturers – but it’s tough when there really aren’t any dealers anywhere near me. Some of the best advice I’ve seen is ‘buy what’s supported locally’.
For tall guys, IMO getting weight moved forwards and down can be a really big deal. If you want to experiment, just sit up and lean forwards onto the steering wheel. If the kart starts turning easily, you’re way too far back. I keep finding that I have to get the weight close at least before any of the other tuning advice will make a difference.