I usually don't do pass-throughs on Dart frog vivs. They increase the complexity and create a new point of escape for thumbnails. However, I always do pass throughs on tree (and leaf) frog vivs to allow flexibility for pumps, heaters and rain chamber use. My first few were really complicated and unsightly, to be honest.
I have streamlined them quite a bit so that they are not only no longer ugly, but much easier to build. The caveat is: you need to plan the top with the pass-thru in mind. I insert the pass-thru in the vent gap, and this requires making the vent shorter, to leave a gap, and to make a terminus to end the mesh before the tank edge.
The first picture shows the pass-thru from beneath, only one cord is going through, but it could hold 2 cords and an airline if needed.
The slide is simply a piece of 1/8" acrylic with a 1.5" slot in it. All of these photos will display foreshortening because there isn't enough room to get in for a straight on shot. It really just sits over an opening and rides in tracks on both sides and tucks into a track on the back. I can slide it far enough back that the is no intersection between the slot and the hole, so if there's no cord, the opening is completely sealed.
The second shot shows the pass thru from above, closed with one cord going through.
The final shot is the slide far enough forward to pass the cord and plugs through it, hence the name.
These versions are really simple and hopefully self-explanatory. I buy the molding that I used for the tracks in bulk from Outwater plastics- since I make a lot of vivariums. If you are near a major city you might be able to find 1/4" edge molding like it. If not you may need to improvise.