My Baker Tech Facts Book says the recommended makeup torque for 5-1/2" 15.5ppf K55 STC casing 2220 ft.lbs; 5-1/2" 15.5ppf K55 LTC casing is 2390ft.lbs. It doesn't list the makeup for speccial clearlance couplingsother than the size: special clearance 5-1/2" coupling is 5.875" diameter, normal 5-1/2" is 6.050".
You might suggest using 2220ft.lbs would be OK?
Also, what is the value for- if you simply want the casing not to fall apart, you could see what torque you need to get to the thread vanish point on the first few joints and then use that- like you do with large diameter casing with API 8 round thread. If it's gas tight then you shouldn't be using API connections, and if you want to be able to rotate the casing, check the torque with the drill string before you POOH and say minimum makeup torque is 80% of the drill string torque (or 2220ft.lbs whichever is less)