Thanks for the post.
Please find below the steps -
1. Run adpreclone on Db Node 1 and Apps Node 1.
2. Copy Database files and Apps Node 1 files to Target.
3. Restore the database and run adcfgclone dbTier - Here will ask you if its RAC or single node.
4. Once adcfgclone on Db tier completed without any error.
5. Run adcfgclone on Target AppsTier 1 - Here it will ask you for Multi Node or single node - Specify single node.
6. Perform if any post steps.
Previously for Cloning from Multi-node to Single node, there was option of Merge. That is "appsTier merge" and "appltop merge".
But in R12, it employs a new concept called Unified Appltop, which means that no matter what you choose while installing, R12 will install a complete apps file system on all nodes. In the case of 11i, RapidInstall copies from the Staging Area only reports on CM nodes and Forms on the Web nodes.
But for DB side RAC has different procedure. For which , please refer Cloning Oracle E-Business Suite Release 12 RAC-Enabled Systems with Rapid Clone (Doc ID 559518.1) >> Section 6: RAC-to-Single Instance Cloning