Mounting TJ flares, need some help...

First off, I dont want people telling me not to use them or how bad they look. They are free and i have to be fully covered to stay legal.

Now on to my questions. My plan is to make them removable for the trail with wing nuts and bolts, I havent counted yet but i think the flares have around 9-10 mounting holes.

Are all of them needed to hold them on at high speed?
Could I use half the mounting holes and be fine?

Also, on a 4door, will bolts work on the door portion of the rear flares?
I want the same design as the front.

No all the holes aren't needed. Just use fender washers to make sure the holes don't rip out.

But you're wrong if you really think you're going to spend 20 minutes before and after wheeling taking off and on your flares and then toting them around in the back of your rig all day. Just mount them solid and call it done.

The holes that are already there are not the best mounting options. They're not designed for the XJ wheel opening. Trimming the plastic to your fender opening and redrilling new mounting holes is a better option. I think I had 8 bolts on the front.

On the rear you're not going to be able to go through parts of the door with a bolt and a nut. I used self tappers where the mounting was blind.

I used 2 pair of rear flares, which I think looks best. I don't like front flares on a XJ.

Sorry, can't help. I tore a set of these off the XJ and installed BW Cutouts where I could use my inner fenders and they reinforce the outer fender.

If you install the TJ Fronts, be aware that to mount them you remove metal that you will need to put back in if you install a different set of cutout flares and that attaching the lower part of the flare is a no-go because once you contour the flare to the body, you just cut off all the mounting points.

If you insist on using that solution, I would try Josh's idea of hunting up a set of rear flares to put in the front. You will need to trim with either solution, but it won't be so bad.

I use a cut-off wheel on flare plastic. Fast, and reasonably clean (looks wise) result.

For the rear wheel opening trimming, I would use the slot and bang method. You cut slices into the wheel opening just past the welds, then you take a 5lb hammer and pound them in and up into the wheel well.
Gives you more clearance and you don't touch the body integrity.