Danny
First off Welcome. And hopefully we can help you on your hitch setup or point you where to go looking. There are a number of us that have gone thru this before and very willing to share our experiences.
A TT hitch, it is a very important part of creating a stable towing rig and we commend you first for asking, and 2nd for trying to figure this out.
To your questions. Using Sunline Fan’s cool collection of Sunline brochures, I found this.
http://www.sunlineclub.com/docs/90.pdf
It is the 1990 Sunline brochure and on page 23 is lists the spec out of the factory on a T274 TT. Is that your TT and your floor plan? It shows the T274 as a mid kitchen layout, front table and rear bunks.
The 1990, T274 has specs of
27’ 9” ball to bumper
As built at the factory with standard supplied options, in the “dry” mode. Dry meaning no gear, no propane and no battery.
3,390# axle weight
530# tongue weight
3,920# GVW
5,000# GVWR
They built that TT dry to have a 530#/3920# = 13.5% dry tongue weight. This is good. When you load the TT you need to try and keep that good tongue weight % all the way up into the 15% range. 15% of a fully loaded TT would be 5000# x .15 = 750#. This now helps you to know what minimum size WD hitch you need.
On that size TT you need to have WD. That is a given. And you need a good sway control system, another given.
Since you are starting out researching and buying, I would suggest 2 brands that can work well if setup correct on your system. They combine both WD and anti sway controls in the same hitch.
The Reese Dual Cam system. The Straight Line system
http://www.reeseprod.com/
The Equal-I-zer hitch.
http://www.equalizerhitch.com/ Note this exact brand as a lot of hitches are referred to a equalizer hitches and they are not the same thing.
Both will give you close to the same towing and anti sway performance. However there are differences between the 2 brands that some times 1 of them fit your personnel situation better. Once you read up on them we can dig deeper into which one and why for you.
If you do the research, you can buy either of these 2 hitches for only a little more then a WD hitch with a friction sway bar. The ability of the 2 mentioned hitches have a lot higher performance for anti sway control then the friction sway bar. The friction sway bar has it’s place and works well where it fits. But again with a little more research and a few more dollars, the Dual Cam or the Equal-I-zer brand will do a better job on your size TT.
Regardless of which brand you get, they are only part of a stable towing setup.
Proper TT weight and balance is the first. Ideally along the way after loading the camper, you go to the truck scales and weigh the rig, and do it in a way where you get axels loads with and without the WD bars on. You should target for 12 to 15% loaded TT tongue weight in relation to the loaded GVW of the camper. The low end limit is 10% but when you get in this area, one wrong gear move in the camper and you can easily go under 10%. There are also ways at home to measure the tongue weight in your yard once you know the entire TT loaded weight. Ypu can them move gear to get the right % if not right. There is a bath scale methods using a bath scale beam and or you can buy for ~$120 a Sherline tongue scale.
http://www.sherline.com/lm.htm
The other big area is proper optimized setup of the WD hitch and sway control itself. The hitch will not work right if not setup right. Once you know what to end up with, adjusting it not that complex but can be a little the first time thru this.
Read up on some of this and if you have any questions, just ask. We are more then wiling to help anyone trying to help themselves setup their rig right for towing.
Good luck on that camper.
John