Minden Fabrication trailers "It's one of the poorest design I had ever seen"

If that's true you are a VERY lucky person!

My club has one of those Swiss made oval aluminium tube trailers containing a Twin Astir RG. The wings go in root first (good) but right wing on the left, left wing on the right, the wings have to be removed and replaced in a certain order as the root dollies, captive to a track, overlap each other, removing a wing involves pulling out a lock, pulling a cable to unlock the dolly, raising the wing tip and moving it to the center, having someone pull a lever to swing the mid-span support out of the way and then carrying the tip all the way out a few inches above the ground as a few inches too high or too low cause the wing to scrape (all bad). The fuselage goes in tail first and is supported by a frame which engages tracks in the trailer. This means that when you pull it out of the trailer the only thing keeping it from tipping over are the people holding it. The tail rides in a captive dolly (and it takes some finesse to get the tail out over the dolly without the tail tip hitting the trailer top) which sits on the ground and does a good job of trying to trip up everyone carrying the wings out.

Oh, we also have a Twin Acro in a trailer where the wings go in tip first on slings (meaning you have to carry the heaviest end of the wing the longest distance possible) and the glider is loaded/unloaded OVER THE TRAILER HITCH! Then there's the enclosed L-23 trailer where the wings load tip first right wing on the left, left wing on the right as well.

You have no idea how happy I was to see that the DG-505 we bought came with a Cobra (and no charge for DG tech support!)

As for the LS-4 vs. ASW-20: yes, definitely one or the other. Probably comes down to whether you feel you need and can handle the extra capabilities flaps give.

Back when Rolladen Schneider went belly up I recall that the type certificate, manufacture and tech support for the LS-4 went to AMS Flight (?) but they never seemed to do anything with it. Now that DG is offering support you'll have to pay for it but you will actually get it which removes the one concern I would have had about buying an LS-4.

So far I've had good support from Eastern Sailplane and Schleicher for my ship with no annual charge - a point in favor of a Schleicher there.