I have some experience related to what you are talking about. I did a wheel swap on our Scamp 16 a few years back.
When we bought the Scamp it had stock 13" wheels and new looking tires. They were from the year 2003 but had virtually no miles on them. Age dictated throwing them away.
The trailer weighs about 2800 pounds ready to camp. The tires were rated 1300 and something load capacity. The right side tire showed considerable squat at max inflation. My trailer must be heavier on curb side. I didn't like the tires being loaded to max. I then investigated other tires that would fit the 13" rims and carry more weight
. I found one available tire that was a little higher capacity, but not enough to make me feel comfortable. Bummer!
Then I began to look at specs for 14" tires. I found one that could carry 1764 lbs. in a smaller sized width. They are Kumho 185 R14C
I did a lot of measuring of the wheel openings and frame width etc to determine if that tire would work. As I remember the size I was looking at had a 25.5" diameter, and would fit under the wheel well, but the axle width would put the tire out just enough to cause trouble with the wheel opening at one spot. I figured that to do it right I would need to shorten the axle length by about an inch.
I ordered a new 3500# Flexiride with adjustable down angle via splined shafts. I mounted it to the Scamp frame spaced down 2" by using 2x2x1/4" tube spacers welded to the frame, and bolted to the Flexiride brackets. The axle center was also moved aft about 1" to increase tongue weight
. I also have a wrangler, so desired the extra lift.
In doing the mod I increased the load carrying capacity of the tires.
Got rid of the aged rubber.
Replaced a 10 year old rubber torsion axle.
Got perfect ride height.
New wheel bearings.
Fine adjustable ride height.
And it works really well with no ill effects.
having 2" additional height would hurt fuel economy, but I don't have a clue how much. I averaged 13MPG on last years Moab trip. Not too bad for a lifted Jeep with 4.56 gears and big mud and snow tires. Jeeps are shaped like bricks.
Stability differences could not be felt. The rig corners flat even in a drift. I have been in some hairy crosswinds, and you can certainly feel the gusts, but I can't say it was perceivably different than stock. I passed 2 other tt's that were on their sides. (stickies) The highway patrol had closed the highway to all rv's and 2 wheel drive vehicles, but let me pass. I cruised along about 25mph. in 4WD through the blowing snow and sleet with no issues. The little Scamp just followed along with no weirdness. I was very cautious with the brake pedal, as in not using it!
I have been able to access some pretty remote camping spots out in our local desert without worry of ripping the plumbing off the bottom just by doing the 2" lift, and using the proper draw bar to keep the trailer level.
I have never changed the Flexiride from the stock 22.5 degree down setting.