The larger the tire the better it will work on the sand.
By you going for a 235/75 to a 255/60 will be wider but smaller overall.
You would need something like a 295/60 to be close to the same circumference.
Keep in mind when airing down it's not only about the width, the length of the tire also gets longer.
You can't notice the longer footprint from the tread marks however it makes a world of difference.
A handy tire size calculator can be found here - - > http://www.1010tires.com/TireSizeCal...bmit&reset=yes
For a performance issue, unless your adding a lift kit any tire you can put on it now should not be noticeably difference in performance.
It's not like your running the 1/4 mile with every 10th of a second being important.
As for a Jack there are to ways of thinking.
1 to change your tire.
2 to get unstuck.
A bottle jack under your axle is all you need to change a tire.
And a HI/lift is ideal for getting un-stuck but it takes up a lot of space to store.
You need a board to place under either one.
IBSP rules say 12"12"