Hey, Deb!
Wasn't on the net much this weekend, so just catching up, again!
David made a good call on angling the bottom of the fill tube so it doesn't sit flat on the bottom of the bucket and stop the water up when you fill. Thanks, D!
Regarding how much of the fill tube goes through the colander - not important. You just want it as close to the side of the bucket as you can get it, so you can center your plant in the eBucket.
Regarding the TYPE of colander you buy -- my only test is to put it on the floor in the store, kneel down, hold it on each side, and lean my weight into it. If it holds me up, without collapsing in the center or on the sides, it'll hold up a bucketful of wet potting mix, LOL!
You did a great job!
Once you gather up all your components, you can put an eBucket together in about 3 minutes!
P.S. Just remember to size the length of your fill tube according to what's growing in the eBucket! Consider how lush your foliage might get (or not). Trying to find a short fill tube in a forest of tomato vines is a total pain, LOL! I usually cut about 22-24" for the tomatoes. It'll look funny, at first, but once it's surrounded by all that greenery, you'll be very happy.
Hugs!