You are very welcome, my friend. I'm back on Mypal now, and find it to be the perfect browser for my needs. It uses a little more RAM than some other browsers I've tried, but that's to be expected since, apparently, version 28.x.x (I'm on 28.1.0 now, which is based upon Pale Moon 28.1.0) is actually a Firefox 52ESR derivative (it's now built upon the 52ESR-based UXP engine which Basilisk also uses). It is perhaps the best actively maintained XP browser, since it will continue to get security/stability fixes (unlike FF52ESR), retains the pre-Australis interface and as a result the ability to use classic themes/extensions, and has out-of-the-box support for online video (MP4 is activated by default but H.264 has to be activated via the Options menu). It also works without a hitch with Flash Player if you decide you want to install it, whereas older Firefox versions now tend to be flaky with Flash (even older versions that came out around the same time these older FF versions did).
I can't see myself using any other browser but Mypal now, and at this point I'm done tinkering with other browsers. Mypal may not score as high as a lot of other XP-compatible browsers in the HTML5 test, but it has been optimized for near-flawless compatibility with the modern web. These synthetic tests can only tell you so much about a browser--if it works, it works. Period!
I do remember you telling me that there are certain extensions which keep you on Firefox since they don't work with Pale Moon/Mypal. If you rely on those extensions every day and feel that you truly need them to be able to get the most out of your browsing, then my recommendation would be to either stick with Firefox 52ESR for now (though it won't be getting any more security updates) or consider using Centaury, a Basilisk fork for XP (which is more of a heavyweight browser than Mypal but has the FF52 feel you're familiar with and is compatible with nearly all of the same extensions).
The latest version of Mypal can be found here:
https://github.com/Feodor2/Mypal/releases/tag/Mypal (look for "mypal-28.1.0.win32.installer.exe")
For Centaury:
https://github.com/Feodor2/Mypal/releases (look for "centaury-52.9.0.win32.installer.exe")
As always, I pray that this info will be helpful!