It’s good to research these things. I see from your forum profile that you are starting out.
You need a descent case. The access case you show there is decent but it is an old school plywood case. It will do the job but you could probably buy one closer to $100.

Consider what you need. If you are carrying your instruments to lessons and jams, a gig bag might make sense…something light and portable. That banjo is heavy enough by itself.
If you are looking for protection, a fiberglass case may make more sense. Calton is the high end. However, Crossrock is pretty good and lots cheaper.
Consider your need. I’d probably pass on the plywood case

Access works.  Crossrock and Superior #1530 also.  All well made.   All should be in the $200 range.  Guardian offers a decent case in the $160 range.  

Nothing wrong with a plywood case for this banjo.  (Or for any banjo, for that matter, as long as you're not checking it in airline baggage. ) 

What do you mean by the "right" case?  Is there some specific feature you are looking for?

The most important feature is fit. My Crossrock CRW720BJ swallows the GT, and my TKL Concept is only slightly better. Both require handtowels to get snug.

Primary use is storage (vertical rack) and protection at home. Actual travel unlikely. I'm trying to spend less than $200. I would also like the case to add value and interest, should I ever decide to sell the GT.

I know what you mean about loose fit cases.  Have had to send one brand  back.

I have a Superior CD 1530 case in which the Sullivan Thunderbolt lives (this is NOT the "bump" case but the regular case).  The banjo dimensions replicate a Gibson.  Resonator about 13-5/8.  Case diameter about 13-1/2.   So the padding holds the banjo perfectly, no movement.  Solid neck support.  Sturdy, comfortable handle.

Since you asked, that's what I'd recommend.  

Regardless, I have found that you always have to try the specific banjo in the specific case.  Not only for the resonator fit but also for the neck fit, neck angle, and how the peghead and heel are supported.  Should be able to get the the Superior with return privilege.

Good luck.