roll bar

[ozzy1]

There is actually no requirement to have a rollbar at all for IVA.If you have one then i personally would want it to offer some rollover protection so it will likely need to be taller to offer this.I recall Spud was about 6'6" and had to have his made larger.
With regards to the seats i see it this way;if you have a steel floor welded in then bolt it through it.If you have an aluminium floor riveted on then i would put in support strips of 5mm across the 450mm width.