Well, on my first LR3 I bought the "Stormer" Range Rover Sport SC wheel that was either 20x9 or 9.5, however the tire barely fit next to the upper control arm, though it did just enough. The tire was a Toyo Proxes ST in 285/50-20. It looked great due to being so flush with the wheel arch/flares but it also rode incredibly well due to not being a chunky MT or even aggressive AT. Cornering was also far better than with those other tires.
That was on an entirely stock set up so there was no need for a taller tire. What you're considering doing will not work with the fender flares unless all you do is stay on pavement. The width of both a 305 but also on a 9" wide wheel, that also has a wide offset, is almost certainly going to grind into so many points of contact, more than where the normal modifications are done and possibly more than non-extensive mods can account for in practice.
Personally, I like to know I can even go into a city parking garage, drop the suspension, and turn 100% as needed without grinding stuff.
I use a 33.7" KM2 but it's 285 wide and on 8" wide factory wheels that have a 53 ET. I tested these with my 25mm spacers and it was just no way once any flex pushed the tire upward into the fenders. This was even worse at the front bumper and it's ARB design even has more clearance than a factory shape.
I listed a tire that ought to work previously. It was like 285/55 or 60 -20. 33" will work a lot better than any amount over 33". 32" works WAY better than 33. At 32 you could actually probably get away with whatever width you wanted.
Now if you don't care about rubbing stuff or being able to flex it off road, then just try whatever makes you happy.
Might want to think about the spare location seeing as none of those will fit underneath.