I’ve used all the floor windows. The bigger the better.
The standard floor window is my least favorite being the smallest. Dart aftermarket floor window is okay. Their oversized window is a little better. The best vertical reference floor window comes from Chinook Aviation. It extends 9 inches aft and 2 inches inboard of the standard window.
The Swiss Solutions Max Visibility Kit is the best product for Vertical Reference work. If you have enough work to justify the cost go for it.
Extensions and having to lean all the way out on the right side is extremely difficult and certainly not appropriate for mast work or setting any precision loads. I’m 6ft 2 and wouldn’t even consider this as an option.
Left hand drive is okay not ideal.
The MPVK or the the super sized floor window is the way to go.