Hi there Brian.
Hopefully, I can answer this question for you. I have a Standard Stealth Slider.
The head i use is also a Manfrotto 504HD Camera Head. This does carry a certain sturdy weight, but needs solid support legs below.
You mentioned the Manfrotto 546b Tripod. This is fine to use, but in my case, i have the Manfrotto 536K Tripod (Carbon Fibre CF edition for lightweight and industrial strength). As you know, both the 546b and 536k tripod has a 100mm Ball Mount, where you screw in the 504HD Manfrotto head for seamless connection with the tripod legs.. The advantage of either the 546b tripod and/or the 536k Tripod is that they both have a 100mm BALL MOUNT. So later on, iyu might need to get a new Head, … so you can add something like the Kessler Hercules 2.0 head with ball mount to screw onto to your Manfrotto 546b tripod legs
But about day-to-day use with the Stealth Slider:
To mount the 504HD head to your Stealth Slider, use the camera plate that comes with the 504HD. Connect the 504hd Camera plate to the undercarriage of your Stealh Slider.
Then slide the undercarriage slider with Plate attached onto your 504HD head.
To connect Camera gear to the top of the Slider, you need the 100mm Flat Mount Adaptor. Use the Flat Mount Adaptor, to the top of the Stealth Slider plate. See: http://treija.com/host/pichost/kessler/mount11 - then you can put your gear on top to attach your camera.
Vertical sliding is just fine with the 100mm flat mount adapter, but it really depends what camera attachment gear you use. Just tilt your 504HD head (with slider attached) vertically.
In daily usage, it does pretty much okay. It’s pretty solid. But the real test comes when you put lots of heavy gear on your slider, the counter-balance does ‘give’ a little at either end. Not much, just a little. I’m connecting my 2nd Shooter pan/tilt head and Canon 5DMkII on top of my Stealth Slider. and when it slides to the extreme end, it does tilt a little (although it never feels like it’s gonna topple over). And in some cases, you might think you need to put a light stand or 2nd lighter tripod at the end to counter-balance it, but that’s not really necessary. Like i say, pretty robust, does the job. If you have light gear on top your slider (like the Manfrotto 496RC2 http://www.manfrotto.com/compact-ball-head-with-rc2 then you’ll be fine.
But if you have lots of seriously heavy Revolution Heads or other heavy Gear on top, l when it tilts just that little bit, you’ll always be thinking: ‘hmmm… maybe i need a Hercules Head’.