The purpose of merging 2 weak hives into one is to have a large population going into winter.
The cluster during cold weather will be bigger thus more heat is generated.
I believe if you use a queen excluder to start, the bees will be strangers to each hive and fight.
By merging 2 hives by the newspaper method the bees have a chance for there scents to mingle.
What I'd do is merge the 2 hives by the newspaper method and get them thru the winter.
The following spring I would split the hives.
If it has a large population you can split the hive in the spring 4 ways.
I would rather have 1 live hive in the spring than 2 dead weak hives.