How can I pass a percent sign (%) value to reg.exe?

There are occasions when you want to add a value but you don't want to add the enclosing quotes. However, when the value needs its own quotes owing to a space character in the string you'll find that it doesn't parse the caret properly. I discovered that it works if you store the string as a variable first, e.g.:
set MyDocsRedirTemp="%HOMEDRIVE^%\\My Documents"
reg add "HKCU\\Software\\Microsoft\\Windows\\CurrentVersion\\Explorer\\User Shell Folders" /v Personal /t REG_EXPAND_SZ /d %MYDOCSREDIRTEMP% /f
set MyDocsRedirTemp=

One problem I have had is to have a variable in a .cmd file include a percent sign literal in a variable, and then to use that variable correctly. It seems to make it work correctly, I needed to use more than two percent signs.

Check this out, executed from a command file:

rem Let's see how a percent sign is interpreted
echo 1
echo %
set x=%
echo %x%
echo 2
echo %%
set x=%%
echo %x%
echo 3
echo %%%
set x=%%%
echo %x%
echo 4
echo %%%%
set x=%%%%
echo %x%
echo 5
echo %%%%%
set x=%%%%%
echo %x%
echo 6
echo %%%%%%
set x=%%%%%%
echo %x%
echo 7
echo %%%%%%%
set x=%%%%%%%
echo %x%
echo 8
echo %%%%%%%%
set x=%%%%%%%%
echo %x%
echo 9
echo %%%%%%%%%
set x=%%%%%%%%%
echo %x%
echo 10
echo %%%%%%%%%%
set x=%%%%%%%%%%
echo %x%

rem Let's see what happens if we try to put a percent
rem literal in a generated file
set file=x.cmd
echo echo off > %file%
echo echo 1 >>%file%
echo echo % >>%file%
echo set x=% >>%file%
echo echo %%x%% >>%file%
echo echo 2 >>%file%
echo echo %% >>%file%
echo set x=%% >>%file%
echo echo %%x%% >>%file%
echo echo 3 >>%file%
echo echo %%% >>%file%
echo set x=%%% >>%file%
echo echo %%x%% >>%file%
echo echo 4 >>%file%
echo echo %%%% >>%file%
echo set x=%%%% >>%file%
echo echo %%x%% >>%file%
echo echo 5 >>%file%
echo echo %%%%% >>%file%
echo set x=%%%%% >>%file%
echo echo %%x%% >>%file%
echo echo 6 >>%file%
echo echo %%%%%% >>%file%
echo set x=%%%%%% >>%file%
echo echo %%x%% >>%file%
echo echo 7 >>%file%
echo echo %%%%%%% >>%file%
echo set x=%%%%%%% >>%file%
echo echo %%x%% >>%file%
echo echo 8 >>%file%
echo echo %%%%%%%% >>%file%
echo set x=%%%%%%%% >>%file%
echo echo %%x%% >>%file%
echo echo 9 >>%file%
echo echo %%%%%%%%% >>%file%
echo set x=%%%%%%%%% >>%file%
echo echo %%x%% >>%file%
echo echo 10 >>%file%
echo echo %%%%%%%%%% >>%file%
echo set x=%%%%%%%%%% >>%file%
echo echo %%x%% >>%file%
echo pause >>%file%
type x.cmd
x.cmd

Was just having this problem and here's what:
If the example line is put in the command prompt it will work.
But, if that line is put in a .cmd or .bat file it will not!
Here's a .cmd/.bat compatible line (double up on percent signs):

reg add HKLM\\Software\\sav /v test /t REG_SZ /d "\\"%%userprofile%%\\""

This didn't seem to work for me...now I get just the caret...here's the syntax I am using:
REG ADD HKLM\\SOFTWARE\\Classes\\Property.Script\\shell\\Edit\\command /ve /t REG_EXPAND_SZ /d "\\"%ProgramFiles%\\Desktop Publishing\\Notepad++\\notepad++.exe\\" "\\^%1\\"" /f
and...
REG ADD HKLM\\SOFTWARE\\Classes\\Property.Script\\shell\\Edit\\command /ve /t REG_EXPAND_SZ /d "\\"%ProgramFiles%\\Desktop Publishing\\Notepad++\\notepad++.exe\\" ^%1" /f