Holly shrubs and trees are very tolerant of pruning in general. I have cut chinese and japanese hollies back to bare trunks before and they rebound.

The best time to cut them down if looks are important is February because they leaf out best then. In the heat of the summer, it will be a little tougher unless you can give them regular water - they will need that.

Thank goodness they are tolerant, because I do not have a green thumb! We can give them lots of water, so if I cut all the leafy parts off, how long do you think they'll be bare?

It could be a month even. Then you have a slight risk of having growth that is not quite hardened off (that is, mature) when the first frost/freeze arrives. If so, that part will turn black and you have to cut it off (could just be the tips).

If it possible you could prune them about half way now to get them closer to what you want and then do the whole job come February?

That sounds like a good plan. Thank you so much!