My '92 has a similar issue, I've found running seal conditioner helps a lot.
When using 5w30 Mobil Clean 5000 (dino oil) and 1/2 a bottle of seal conditioner it went from using up to 1quart every 2k miles to using none (as far as I could tell on the dipstick) over the course of 3k miles.
I stopped using the seal conditioner and the use started back up slowly so I changed the oil and decided to switch to synthetic. I put 1/2 a bottle of conditioner in there again and at first it used at least 1quart every 1k miles but after about 1500-2000 miles (and the other 1/2 bottle of conditioner) it's down to using next to nothing.
Whether it took a while for the seals to adjust to synthetic, or it took longer for the conditioner to work it's way into the seals b/c of the synthetic I don't know.
I use bardahls stop leak with seal conditioner myself. To my knowledge, not directly from the company, it isn't really supposed to swell the seals, just condition them.
From what I've been told, something that swells the seals really isn't a great idea unless it's a last resort to avoid replacing the seals.
Keep in mind that before I used the conditioner I ran a detergent (mild, leave in type, not a flush) in the oil a couple times b/c there was so much sludge and varnish in the engine. No more sludge that I can see but still lots of varnish, which is why I'm running a diff. type of detergent in there right now.
I'm sure it would be wiser to run a conditioner product and a detergent seperately but I don't do a huge amount of driving so I get impatient
h:
Anyway, some detergent additives are real thin and so have a seal sweller in them which is why when I ran only CD-2 Max detergent, the oil use completely stopped but came right back after an oil change, when I used it a 3rd time, after using seal conditioner, it didn't swell the seals and so oil use went up.
In the past I've tried running thicker than recommended oils (way overboard in one case) to try and stop oil use and it never worked, only slowed it a little. However, those cars seemed to have mechanical issues whether worn rings or broken o-ring(s) so for all I know it might work on a car like mine that appears to have little to no wear on the piston rings and seals that appear to at least be in one piece.
Hope that helps
sorry it's so long.