Craftworlds: How to make a Heavy Weapon Platform heavy army work?

Ok, so hear me out.

I have nine Heavy Weapons Platforms. All magnetized for any of the three weapon options.
I had an intriguing idea, wanted to build them, love how they came out.
In game terms, using all nine is of course expensive. And extremely inefficient. And sub-optimal in every way.
I also built two units of Dark Reapers because I had an idea on who to make them look cool.
That's pretty much how I make my decisions.

I've only recently managed to start trying to use them as an army, coupling them with a trio of Farseers and a pair of Wave Serpents, and padding the army with Harlequins. And a few Guardians.
It has been very sub-optimal. Harlequin infantry it turns out is quite rubbish. Still absolutely love my Death Jesters though.

So - thoughts?
How can I make a Craftworld gunline army heavy on Heavy Weapons Platforms and some Dark Reapers work?

I'm still going to continue building stuff just because I have a cool idea. I'm just trying to come up with ideas on what to add to the army to make it work better.
Yes it's silly. I like silly.

No wrong answers, open to all ideas. Hit me with what you've got.

for sure, one custom i REALLY like for an Aeldari gunline is the "Swift Strike" and you can combine it with "Masterful Shots" or "Hunter of Ancient Relics", but the Swift Strike is essential, especially with Heavy Weapons.
The fact that you can than advance and then shoot your heavy weapons with no penalty is just insane.
Also nice with Battle Focus

As for units, i have nothing at the moment to add, except the Wraithguard, War Walker, Wraithlord etc...

Dark Reapers are so much better than i thought at first, and the Dire Avengers are also really cool to play.

However, i'm not really familiar with the Harlequin :/

Oh wow, those conversions are sublime.

I'm afraid I can't offer much tactical insight as I'm not familiar enough with Craftworlds.

That said, I had been wondering about the viability of both Dark Reapers and Support Weapons in a Ynnari list (as one dead model would mean the rest are hitting on 2s). For the latter, the idea would be to have 2 D-Cannons plus a Shadow Weaver. All three can ignore LoS, and if the squad takes fire, the cheaper Shadow Weaver can take the hits and grant the (hopefully) surviving D-Cannons the Ynnari bonus. Admittedly, though, this idea might not be as much use after the nerfs to ignore-LoS weapons. Still, I thought I might as well mention it in case it's of interest. If nothing else, your army certainly has the right aesthetics for Ynnari. xD