Hi Al,
Thank you for providing lots of information with your post, especially a description of the escapement characteristics and the pendulum free swing test. It is surprising how many people expect debug help by asking "My clock keeps stopping, what should I do?".
If the escapement is energetic, then the entire gear train is likely in good shape. This usually narrows it down to the pendulum support bearings, but the free swing test runs for >15 minutes. The bearings in the kit have a dry lube added for rust protection. Sometimes they work slightly better if you remove it using alcohol.
Sometimes, a pendulum that slowly degrades over time is an indication of not enough drive weight. 4.5kg should be more than enough to keep SP13 running. One caution is to make sure that the frame adjustments are made to keep it from sagging with the extra weight.
All of the things you have done should produce a working clock.
My suspicion is that the involute gear tooth profiles could be the issue. I was always under the impression that involute and cycloidal gears have similar efficiency. Both styles have a mostly rolling action with very little friction. There is always some sliding friction as the teeth start to engage and as they disengage. Friction is higher if the engaging occurs before the line of centers because the teeth push into each other. Friction is lower after the line of centers where the teeth are pushing away.
Involute gears have much more engagement before the line of centers compared to cycloidal gears. Adding extra drive weight sometimes makes the teeth jam together harder. Some filament brands have higher friction than others and I do not know any good way to test them other than to build a clock. A simple fix is to add a very thin coat of lithium grease to the pinion teeth. You can wipe most of it away, so it is nearly invisible. Only the pinions need to be greased.
I have started converting many of my oldest clocks to cycloidal style "Perfect Print Gears". So far, SP2, SP3, SP4, and SP5 have all been upgraded. These were major upgrades because I ended up redrawing the entire frame. The newer clocks should go a bit faster. I am currently converting the SP14 moon phase clock and will start on some of the others next. The biggest difference is that the clocks are more reliable. For example, the 32 day clock used to just barely stay running in 32 day mode with an 11lb weight, and it might randomly stop every few weeks. The new gear profile is extremely stable with a 9lb weight.
Sorry for the long winded description of telling you to try lubricating the pinions.
Steve