I tried a 92 and a 95 Caddie radiator from the 4.9 deville. both had a 1" thick core, which is the same as my SSEi, same as the replacment for the SSEi. 30x17 are the dimensions. Napa showed no other radiators available for the deville with the 4.9. Perhaps its a napa thing and they are not made as thick as other (aftermarket) radiators.
The 4.9 rad had the oil cooler lines as well.
Napa Price out the door for the direct replacment radiator is $205. Radiator Express is not an option for me considering my location
I'm 90% sure my 98 has a 1" thick radiator from the factory, I did not measure it but looked at it briefly, I will measure when I get home. it looked like 1" but may be skinnier.
If there continues to be cooling problems, I guess I'll need to go to a trans cooler.