Man, there is some confusion here for sure.

To be clear, if your LD player has an optical output and your receiver can decode DTS Surround (5.1) then...you have it. No need for "experimenting" it's simply called "using my equipment for the exact purpose intended." Since DTS fits entirely in the PCM bitstream, "compatability" isn't an issue. Players made before DTS even existed will still pass the signal through the digital out.

However, a 2.0 channel DTS is just PCM stereo. There wouldn't be any reason to do it otherwise. It's just a way to avoid paying for the Dolby Stereo logo. There were several "systems" designed this way for the same reason and I don't think any receiver will ID any of them as anything but "stereo PCM", not only because it's exactly the same but also because receivers that could ID anything were probably all invented after this this time period.

The trick is to have an actual DTS LD, of which there are few, and far fewer are worth owning.

Not all, as there is one version on LD which has DTS 5.1 audio.

So this had a DTS stereo release and then a Dolby digital release?

New Line used DTS exclusively on "The Mask." DTS offered a "Dolby Surround" compatible 4:2:4 soundtrack on the feature prints, called DTS Stereo. Since using "Dolby Surround" or "Dolby Stereo" would require the payment of royalties, the DTS stereo option was covered by the royalties already paid for DTS 6-Track.

That same 4:2:4 track is what all 2.0 channel stereo programs for "The Mask" used. No Dolby royalties on the video if they don't say "Dolby" on the jacket, and provided they didn't use a dolby encoder when making the 4:2:4 track.

For the Dolby Digital LD, the PCM track is still the DTS Stereo mix. On the DTS LD, the Analog tracks are DTS Stereo (incorrectly listed here on LDDB as Dolby Surround).