In most of my outdoor boxes I just run the cables out the bottom and don't worry that it's not perfectly sealed. I make sure it's sealed enough to keep the bugs out.
I've used:
1) Conduit to junction box
2) In Wall / in soffit to junction box
I normally do not like to run exposed wires ..
If I were to run exposed wires, I would run a drip loop before coming up into a junction box .. you can use something then to seal up the remaining space in the hole on the bottom on the gland like a Duct Seal Compound
( as Tigerwillow1 points out, I am more worried about bugs getting up from the bottom, .. )
I'd just stuff the Duct Seal into the hole keeping the cables in the middle, away from the threads to avoid scuffing/cutting. No gland needed that way. Alternately get a 3/4" threaded fitting, romex connector or whatever, and use Duct Seal with that.
Funny enough I've been looking for 3/4 glands that aren't comically large for the opening - None of them seem to be small enough to be a tight fit on the Cat5/6 cables and always needed that duct seal putty or such to fill them up.
If anyone finds 3/4 glands that allow ya to drill your own hole size or fit network cabling closely, please do link it