I have read multiple times that low-trail forks are more stable under a front load. Does this additional stability apply with a top-front load, a low-front load, or both?

I'm sure to have others disagree with me on this, and theoretically they have grounds for solid reasoning, but I have never found a significant difference in stability with a low rider vs a higher riding front rack/panniers as long as I keep my heavier stuff on the bottom.

OK, I haven't been able to try a significant top-mount load, but I got put the low-rider rack and bags on my low-trail bike, and it's just magic. I rode with about 30 lbs split between two bags, and it's simply amazing how the low trail makes the weight simultaneously stabilize you, but also makes the bike feel very nimble. Like, you can tell when you're climbing or accelerating, but the combination of low trail and a low-mounted front weight makes the bike handle like it doesn't have a load at all.

Good to hear that you have a good handling system. But some front racks do not have a 30 pound rating. You probably can exceed the rating some, but I would not want to risk a rack failure.

Tubus Tara has a 33-lb rating.

https://www.biketiresdirect.com/prod...UFwxoCgh_w_wcB

It's a good chromoly tubed rack.

Im not sure what my touring bike's geometry in terms of trail is. With that said...

I just rode a few days with rear panniers mounted on a front rack that has high and low mounting points.

70% of my total gear weight was in those bags and 30% was in a dry sack on top of the rear rack.

I found that it rode the same regardless of if the bags were mounted high or low. I could climb out of the saddle a lot easier than with a significantly rear loaded bike too. The front weight was stable and syeadied steering in both high and low mounting

Again, not sure what my bike's trail is though.

It's pretty easy to measure, but as a guideline a fork with a lot of rake has lower trail.

I've carried significant loads (but didn't weigh them so can't quantify "significant") in an Acorn Large front bag sitting on a small Nitto rack on a 650b bike equipped with 42mm Hetre tires. The trail is 30mm. It rode well. Turning took more effort than it does with lighter loads up front, but the bike held its line well even in the wind.

I've also carried lighter loads in an Acorn Boxy Rando bag on a Velo-Orange front rack on a 700c bike with 28mm tires. The trail is 56mm. It also rode very well. Turning wasn't negatively affected---at least not to the extent I could tell---and the bike held its line well even in windier conditions.

Finally, I've carried light loads in an Acorn mini-rando bag (no longer made; it's like a small rack trunk for the front) on a small Nitto front rack on a 700c Sam Hillborne with 33.3mm Jack Brown tires. I believe the trail is in the high 60mm's. I didn't like it much; even in fairly mild crosswinds the bike was wobbly. I had trouble holding the bike to a straight line even with the small winds.

That's all I can add to this discussion, but based on my experience I've concluded that a load on top of a front rack is okay on a low- or mid-trail bike, but destabilizes the steering on a high-trail bike. Others have claimed no negative effect of higher front loads on steering on Sam Hillbornes, so my experience differs from that of most people I've seen write about it. I've not tried front panniers on any bike yet, so can't comment on that beyond what I've read from others.