I prefer to do them cross-armed :ohwell: :ohwell:

there is no distinct disadvantage to doing them cross-armed, and many people prefer it this way as your delts provide a nice shelf for the bar to sit in. As long as you are conscious of keeping your arms up it is fine.

The disadvantages are:

1) With a clean rack, it's much easier to dump the bar, if necessary.

2) With cross armed, one shoulder sits slightly higher than the other, which knocks on to the spine and the hips. I prefer to be aligned nicely when squatting.

The bar sits on the shoulders whichever way you do it, and if you lack flexibility to do it with a clean rack, I personally think it is better to address that issue and gain the required flexibility, rather than just ignore the problem.

If you're struggling to use a clean rack for front squats, work on thoracic mobility, and external rotation at the shoulder, it's unlikely that the wrists are actually a problem.

In the meantime use lifting straps, wrap them around the bar, and then grip the straps, so that your hands can be a bit above the bar. Like this -

Also with a lighter weight than you normally work with, do front squats using straps normally. By using the straps, you will get a good stretch, but only go as far as is comfortable, don't injure yourself.

If you want any tips or drills to work on the mobility mentioned above, just ask.

Another consideration semi-related to wrist and elbow flexibility is that you may consider placing your heels on a small block of wood. It's sort of equivalent to doing them on your tip toes while still allowing you to push off the back of your feet. It semi helps with flexibility because you don't lean forward as much. SOme would argue that this is poor form but olympic style lifters wear shoes that do virtually the same thing. The lifting shoes either have a heel or some sort of elevation to them that allows the heel to be higher than the toes.