The recommended way is different, but in preparing this message I just discovered I goofed in preparing the 4.4.4 installer package. This is supposed to contain two versions of polyglot, called polyglot38.exe, and polyglot.exe. The latter is the one automatically used when using /fUCI (or from PSWBTM the /%sIsUCI=true) options, and was supposed to be Polyglot 1.4.46b. It seems, however, that it is just another copy of Polyglot 1.4.38x. I must at some time have tried something out in the wrong folder, from which the distribution is prepared (I have dozens of folders on my system called "WinBoard", and containing the same files, just different versions...). What a mess.

The dual Polyglots were (err, should have been...) included because there is a different need for users that were already using WB+Polyglot, and had existing polyglot.ini files around they wanted to keep, and first-time users, that still had to make all polyglot.ini files from scratch. Polyglot 1.4.46b served the needs of the latter much better, by highly simplifying what you want to do here.
Let me tell you how it is supposed to work:
After specifying the "WBopt /%sIsUCI=true", click "Save", "Save Changes", and then "Launch Engine". WinBoard will fire up, and you select "Engine #1 Settings..." from the "Options" menu. This will pop up a dialog where you can aconfigure the engine settings. In this dialog, there is a checkbox (with the Polyglot options) "Persist". Make sure it is checked. When you leave WinBoard then, Polyglot will automatically have made a polyglot.ini file (with a name derived from the engine name) in the _PG folder, and use it next time when you use that same engine.
So you will never have to move, copy or edit polyglot.ini files. In fact you would not even have to be aware they exist (or even that Polyglot exists). Invoking Polyglot is always done through the WB /fUCI option, and altering the contents of the polyglot.ini file (or looking at the current contents) is always done through the WinBoard menu dialog for Engine Settings.
To use this method, you would first have to download the appropriate Polyglot version, though, at
http://alpha.uhasselt.be/Research/Algeb ... .4.46b.exe (direct link), and rename it to polyglot.exe in the WinBoard folder (deleting the existing polyglot.exe). I am really extremely sorry about this...
The polyglot38.exe was intended for use with existing polyglot.ini files, pretty much in the way you are doing now (except you first have to create an existing ini file by hand through first making, and then copying the polyglot_1st.ini). They would just point PSWBTM to polyglot38.exe, and give the name of their existing polyglot.ini file (which would likely not be in the _PG folder, but that would not matter, as long as they gave the correct path name) in the "parameters" field.
So under the circumstances (not having Polyglot 1.4.46b) you did found the optimum solution, but it is very much more cumbersome than was intended. I will in any case fix the download, and think about how to best provide a way for people that have already downloaded to get the correct Polyglot.