There's no written reference material that backs this up to my knowledge, but I can assert from experience that CLB 1 thrust would definitely be higher than a high assumed temp R-TO thrust. It's policy in my organisation to always use CLB 1 or higher.
Typical 22 K lightweight 700 assumed temp takeoffs at an OAT of 30C with assumed temp of about 68C result in an R-TO N1 of some 86%, which rams up to 90% R-CLB at thrust "reduction" height!
Haven't seen this occur at CLB 2 values though. The reason could probably be that 737 FMCs allow a max assumed temp of 70C precisely to cap it conservatively at 20% thrust reduction although the hypothetical limit is 25%.