Notwithstanding WILT's excellent points & diagram of grade 8 physics leverage principles...
Perhaps, you could creatively use some of your existing on-location equipment weight, (rather than inconvenient, heavy sand bags).
Just one approach, but here is what I utilize for occasional destination-weddings (I always try to operate with minimal amount of gear).
Motto: Less is often more!
For fast, dynamic on-location portraits & any time-constrained weddings, I try to avoid sandbags, but never compromising safety, clients, public, or lights.
[But if I do use them, I have one or two these very compact Matthews BOA 15lb bags, which are manoeuvrable & 1/3rd the size of traditional saddle sandbags.
If I use a Lastolite 6ft x 6ft scrim or large California Sunbounce then use 35lb bags.
Instead, I usually prefer to use my existing light bag & lightstand bag for ballast, placed/hung (with a nice discrete refined black twine, with clip)
with top of the small twine approximately 3 feet up onto one of the lightstands adjustment knobs, on each of the two Manfrotto #1004BAC lightstands and the bag then draping down the remainder of the light stand.
If windy, then on the windward side which will likely be receiving any lateral force/wind;
or if no wind, then on the opposite side of either of my Profoto B1's, for counterbalancing & ballast.
i.e. One existing equipment bag as ballast, for each 12 ft Manfrotto #1004BAC light stand. This setup works well, is effective, efficient & enabling fast set-up/tear downs!!
- a Profoto Double Bag:
[which also holds spare Profoto B1 batteries, B1 battery-charger, barn doors, grids; when hanging as ballast obviously excluding 1 or 2 Profoto B1's]
- a Manfrotto lightstand #LBAG110 Bag:
[which also holds, 1- 7ft Matthews Reverse, grip hardware: such as 2- Manfrotto Justin clamps, 2 Manfrotto #026 umbrella adapters, Surui #P-326 monopod for a strobe or speedlight light-stick, Profoto Deep Silver- Medium umbrella with front cover, Profoto 2ft Octa softbox (with rods & diffusers in place to minimize set-up/tear-down time); which when hanging as ballast obviously excluding the 2- 12ft Manfrotto #1004BAC lightstands].
While not in the intense Florida sunshine you have to contend with, I from May to September for outside on-location applications, after positioning subjects & camera positions utilizing existing ambient lighting, often prefer bare Profoto B1 strobe, (with its built-in frosted glass front, or with OCFbarn doors, or feathering) to balance the sunlight, or to create highlights, to direct a viewers attention, rather than wind-catching power-eroding light modifiers.
If you have an assistant, just use a light stick, rather than a light stand.
for example see this Jason Lanier video: https://www.youtube.com/watch?v=4zf_XPZnvXk (29:29 minute video)
I have my assistant use the Surui P-326 monopod, which I find works well. It's subtle, fast & helps accuracy.
I'm a petite 5ft 2.5 inch female.
ALSO (important point),
Sometimes the less conspicuous more discrete you are, the better.
e.g. no light stands and particularly no light stand support wires/lines. (no photography lighting permitted, or light-stick only city by-laws)
In an increasingly populated world, you know better than I, that most cities (& even towns), tend to hinder rather than help professional photography activities with their ever restricting policies, or required permits with increasing city-fees.
Just one view & thoughts.
Good luck & continued success.
Otto, I enjoy your (& your wife's) photography work, observing it over the internet. You have progressed magnificently since approx 2009, when you were intensely studying others work & considering (the switch from Canon to Nikon); you have been a very discerning learner, with an inquisitive mind - well done!
Thinking of inquisitive mind, may I ask which camera you are using now for still photography?
(reviewing your portfolio, I might guess you made the change to Nikon in approx 2012?)
I know it's about the photographer, not the equipment, but the aid of technology, in skilled hands, I think does help in differentiating oneself in the upper-end of a target market.
Pardon me for pointing this out, but on the "About Us" page of your lovely web site, there appears to be a spelling error.
reads: "yatch" (unless this is a casual new unofficial/alternative way of spelling the word in our hi-tech world)
should read: "yacht" (the established way of spelling the word)
since, incorrect spelling may potentially reduce your credibility, with some in the market you are targeting.