The following discusses using multiple SaveFiles/Folders.
As I understand it, your objective is to boot Puppy from a USB-Stick from multiple computers. In order to do that all the applications you are going to use should be located on that Stick so that they are not only immediately accessible, but also that the settings within the Save point to the location where those applications --SFSes, AppImages, or portables-- are found. All SFSes, AppImages and portables can be copies without having to boot pfix=ram*.
I use amethyst's Utility Suite extensively, https://www.forum.puppylinux.com/viewtopic.php?t=1694. The Save2SFS module of that Suite enables you to capture all the content of (or which otherwise would be written to) a SaveFile or SaveFolder within a READ-ONLY advr.sfs and/or ydrv.sfs. No need to boot pfix=ram in order to accurately copy these. The only things in my SaveFile/Folder are settings, customizations and such applications I have yet to 'transfer' into an adrv.sfs or ydrv.sfs.
Consequently, my SaveFile/Folder is very small.. As bigpup and I have mentioned the SaveFile/Folder will have the appropriate settings and customizations for the original computer. These may have to be changed on your other computer. Although the following can be done with any size SaveFile/Folder using a small one conserves space and takes less time.
Puppys can make use of multiple SaveFiles/Folder. When on boot-up Puppy encounters more than one Save, the booting will stop and a menu will be presented for you to choose which (or none) Save to use. When you've booted into a Puppy without using a Save, on shut-down you'll be offered the opportunity to create a Save AND give it a descriptive name by typing in that description. But, having booted pfix=ram or using a different Puppy (or a different Save, see below), you can also Right-Click a Save and add a description.
For example, running Bionicpup64 if you did not add a description its SaveFile would be named Bionicpup64Save.sfs. But say you were going to use your 'Puppy on a Stick' from both Asus and Thinkpad laptops. After creating the first, say with the description Thinkpad, you'll have a SaveFile named Bionicpup64Save-Thinkpad.sfs. You can then boot pfix=ram, Right-Click Bionicpup64Save-Thinkpad.sfs, select Duplicate from the popup-menu, and create an exact copy but with the name Bionicpup64Save-Asus.sfs.
The first time you boot up from the Asus selecting the Bionicpup64Save-Asus.sfs you may have to change some settings, and customizations and Save those changes.
The above will also work with SaveFolders, if your USB-Key has a Linux formatted partition so that you can use SaveFolders.
-=-=-=-=-
How to boot 'pfix=ram'.
(1) Temporarily edit your menu.lst or grub.cfg. If you used grub2 as boot-manager it will create a grub.cfg file with listings each of which will have a line something like this, the relevant argument only colored for emphasis:
linux /bionic64/vmlinuz psubdir=/bionic64 pmedia=ataflash pfix=fsck
If your boot-loader is grub2config, frugalpup-installer, LICK or grub2 from a major distro, grub2 is the boot-manager. If your boot-manager is grub4dos --AFAIK, only now available as a Puppy built-in-- it will have created a menu.lst with a similar line, albeit beginning with the word 'kernel': e.g.
kernel /bionic64/vmlinuz psubdir=/bionic64 pmedia=ataflash pfix=fsck
These are text filed you can open in a text editor and change to read (for example if using grub2)
linux /bionic64/vmlinuz psubdir=/bionic64 pmedia=ataflash pfix=ram.
But you may not need to. IIRC, both grub4dos and grub2config and maybe frugalpup-installer will automatically write one stanza (titled RAM-Mode or NO-Save) including the pfix=ram argument.
(2) A SaveFolder is just a folder with a specific name, but it must be located on a Linux formatted partition. If so, you can create a SaveFolder by Right-Clicking an empty space next to your SaveFile or SaveFolder, select New>Directory and give it an appropriate name, e.g. Bionicpup64Save-Test. Although it will have noting in it, on boot-up Puppy will recognize that there is more than one Save, and present the aforementioned choice to boot without using any Save, i.e., pfix=ram.