I've got a FAL that I want to toss a small red dot on, something like a T1 or a RMR. Frankly, it seems like a waste to spend the money and add the weight of one of the railed dust covers just to add such a small sight.
What I'm curious about is the DSA picatinny rear sight replacement.
Have any of you guys actually used that to mount a sight? This FAL has a fairly tight lockup between the lower and the upper, but I'm curious if having the optic and the barrel on different parts of the firearm will provide an issue. I've heard people complaining about having that issue with iron sights, including people who've shimmed the lower to make a tighter lockup.

I've also been looking at the LTR rail, but reviews of it seem to be sparse, though positive. Any of you guys used the LTR? It's pretty similar to the SUIT/Hensoldt mounts, but I'm still skeptical over mounting a sight to a dust cover with no way to tighten it down.

I wouldn't mount an optic to the lower. Even with a relatively tight upper/lower fit, there is still enough play to contribute to accuracy issues. This is one of the shortcomings in the original design of the FAL iron sights. 

There was a company called Grenadier precision that made a few slide-on rails about 10 years back--they were a good deal lighter than the DSA or ARMS mounts, if you can find one. 

I have no idea if these are still available... but a quick google search turned this up:

http://www.falltr.com/

That style of scope mount has always been suboptimal (regular dust cover that takes a scope using whatever mounting method).

I do wish that DSA would have put into production the lightened version of their scope mount that they made for the ultralight model they made (but apparently chose not to offer for sale after all).

That's kind of the conclusion I'm drawing. I suppose you could try to bed one of them, but then cleaning the gun would be a bitch.

I suppose the best course of action is to suck it up and buy the DSA top cover, IIRC, it's like 20 bucks cheaper if you buy it in combination with a para kit. The brass catcher feature and the fact that you can buy it milled for an ACOG are cool, too.

The DSA covers do look great! Lol