i find a short slider best, the ramping and uniformity of movement is easier to control. The trick is to have a foreground object to emphasise the movement, or to slide out from behind so ething large and close to the camera to do a reveal. add a microball or compact ball head i to the mix and you can use the 502 to tilt the slide, and the microball to compensate keeping the camera level but the movement skewed.
there are sliders than cen be adapted into shoulder rigs, but I haven't used them so cannot vouch.
I like the cowboy slinger, cheap, comfortable, compact, basic, functional, but I tend to shoot with lens and camera only.
If you want to save some serious weight or space, and this takes a leap of confidence.... don't take tripod legs, or settle for a monopod (manfrotto do one with a ball foot which is good for video, can mimic a slider up to a point, and as you alrwady have the 502 head, you only need the leg and foot part) anyway, back to tripod legs...
Not absolutely neccessary, get a manfrotto superclamp and 3/8 spigot. Get a manfrotto 438 (i think) mini leveller.
Now railings, chair backs, tables street furnature etc become your tripod legs... the monopod is steady enough for b-roll etc, the clamp can be improvised, levelled and your 502 head put on it. (or even slider and 502 head)
An extreme solution perhaps... but workable.
Improvisation and confidence are the key.