That is what we need the most this week more than anything else. Fortification of the systems on this spreadsheet from the top down. Stop fortifying at 100%. Right now, it looks like Damoorai is the highest income system still unfortified. Every time you drop something off, use the "1 ton test"; give 1 ton of garrison supplies so that your fortification numbers update. If it still requires the full load, continue delivering. If it is done, move on to the next one, or the next closest one, which is probably Tujing.
As for Expansion in Crime Sweeps, Af Leporis is a good system, but Sirius Gov wanted it back. We wanted to try and work a way of failing that, but right now failing that expansion due to turmoil would lose our control of at least Birite, and while we can handle that, I'd rather not 'aim' for that. So we're fortifying every where profitable, and if we're still projecting a shortfall, we're fortifying everywhere.
Sorry, I drifted from Expansion to Fortification. In answer to your questions, no, it does not matter where you turn in merit vouchers earned at a Crime Sweep.
Our Power over-pummels Crime Sweeps, so we would not benefit from over-doing it.
If your combat ship is the same ship as your fortifying ship, you could take a load of fortification supplies to Sietae, and then proceed to Nurundere and oppose that Hudson expansion
as part of Operation Janus by pummelling Military Strikes. Be aware, there are Hudson CMDRs patrolling the area trying to impose a blockade of the system.
You could oppose Delaine expansions, Winters expansion, or more Hudson expansions. You can find those on the galaxy map by filtering to those Powers and looking for the concentric circle icons. Or you could go to Galactic Powers in your menu and pick a Power > Expansion tab > View on Map.
Additionally, you could fit an interdictor and undermine their control systems. Undermining a control system over 100% has no benefit.
If you explicitly only want orders and don't wish to think for yourself, you might want to sign up for a Lavigny aligned player group. We have
Lavigny's Legion,
Les Corsairs de l'Empire,
Orden Comandantes Imperiales,
Knights of Lavigny (might be inactive), the
White Templars, and the more free-form
Kamadhenu Chapterhouse of Inquisition. The Chapterhouse does not give orders. Everyone else does. However, if you wish to stay in Lavigny space, need no more merits, and want to earn credits in a way that will benefit the Power, check out the
Chapterhouse Lantern. It lists the conflict zones and names the faction who will benefit Lavigny's cause if they win.