Instruction: Extract information from the supporting document to answer the given question.

Input:
Question: How many of these sheets can be put on the dehydrator at the same time? Also, should they go on the top shelves or the bottom ones?
Document: My first attempt to make &#34;real fruit&#34; roll-ups turned out great! Be careful not to overfill these sheets; also I coated mine very lightly with coconut oil before pouring in the puree, but the fruit leather came out quite lovely! If you are using more than one tray, rotate them every couple hours, because the trays on top will dry faster than the ones on bottom.
Love making fruit roll ups in my Nesco Dehydrator. We have used this many a time to make awesome fruit roll ups that are healthier than the ones that are sold in stores. They do take a long time to make, but its worth it in the end. This comes with a set of two, and with the one that we received in the box with our dehydrator, i can make three at a time. Huzzah.
These are cool inserts that allow you to make fruit roll ups etc in the dehydrator, but they also bend which is a real bummer. That means whatever you put into them doesn't lay flat so you get a high spot in the circle. That makes whatever you're preparing either thinner, or bare altogether. That's my only complaint otherwise. I tried to make one of them flat by using my home iron and that worked somewhat...but it was a bit dangerous and the results were still lacking.
I have the Nesco food dehydrator, and needed this accessory so I could make more fruit rolls at at time. It's high-quality and does its job, but I do wish it was a little deeper so I could make thicker fruit rolls; thin ones risk getting crunchy, and I like mind soft. Do lightly oil (i.e. wipe with an oiled paper towel) the try so the fruit roll comes up easily if you want to, but the try doesn't require it.
This is a handy item for making the fruit rolls, but I also use it on a bottom tray to catch seeds when I am drying peppers. It makes cleanup easier.
We already had some of these that came with our dehydrator, but of course, when you decide to order more trays, getting these to go along with them only makes sense. I know they are called fruit roll sheets, but honestly, we hardly ever use them for fruit. Anything liquid, or that may fall through small cracks, we use these. Sauces, hamburger, and all sorts of other things.
I ordered2 sets of 2 fruit roll sheets. I received 1 set of fruit roll sheets & 1 set of mesh like sheets that were too large for my dehydrator. Rather than go through the hassle of returning the wrong sheets, I just cut them down to size & used them. They work OK but aren't what I ordered.
I started making apple/banana fruit leather. The sheets worked wonderfully. They are sturdy and their shape is easier to work with than the original sheets I got with my dehydrator. I put some coconut oil on the sheets prior to putting the fruit on the sheets and they come off so much easier.
These sheets are a decent fit in my American Harvester dehydrator, the center hole is a little bigger than the ones that came with the unit but still fit extremely well. The quality is very good, will be buying more of these.
These things are great for making applesauce fruit rollups. I've also done blended strawberries, which are quite tart without added sugar, and banana+nutella ones which took forever but were very very very good.
Answer: It depends on what's in there, temperature, and more liquids in the dehydrator may add to drying time. Also, it may affect drying evenness, between the layers, because they are not mesh. When I use a few, the top layers are done before the bottom layers, so I just remove the top two layers when they are done, then let it run with the rest of the layers.