Whatever brand you choose, get two identical second stages, both top performance and with a knob for adjusting effort. Using a crap and cheap "octopus" thing is BAD. When you need the secondary air source, it must perform with top performances, as you are already in trouble!
Regarding brands, I would suggest Scubapro: I am big fan of this brand, as they make ever-lasting products, I am still diving my old MK5+R109 purchased in 1976, and they still make parts for servicing it.
Furthermore, a SP reg can be serviced everywhere all around the world, and you can easily service it yourself, as Internet is full of guides, manuals, videos, and sellers of original service kits.
Regarding price, I warmly suggest to purchase Scubapro regs here in Europe by a serious online seller. There are no custom duties for importing regulators in US. You save almost 50 % !!!
They are mostly made in Italy, so their price here are much smaller.
Going in more detail I would suggest the MK17 evo plus 2 identical G260, one with an hose longer than the other, for being easily donated.
I understand the good point about a first stage with the 5th LP port on top (which usually is mounted upside-down, so it becomes "on bottom"), as I dive mostly MK5 and MK10 first stages.
However Scubapro redesigned the port positions in the MK17 Evo, following recommendations from tech divers. Hence that reg is one of the few which, despite being compact and without rotating turret with fifth port, allows for perfect routing of hoses in a twin tank or sidemount setup. And removing the rotating turret means a simpler reg, with less failure points, lighter and also cheaper.
It appears that it is difficult now to purchase the MK17 Evo in the US; but if you buy online overseas, as recommended, you find it easily.
The G260 is the direct successor of the G250, the most successful reg of all times, sharing with it all the relevant parts, but adding a small screw which allows for better fine tuning.
It is simple, robust, and high performances. There are good alternatives (for example the C370, which is lighter and less expensive), but in the end I see no reason for leaving what is known to be safe and good for something more fancy but less known.
A quick search on European EBAY suggests this:
Scubapro MK17 Evo / G260. STUFE MK17 Evo. Stufe G260. Breiterer Mundstücksstutzen. Neuer strömungsoptimierter Kipphebel. Luftaustrittsöffnung baugleich mit A700. Kleineres Gehäuse als G250V (76vs.82mm).
www.ebay.com
You can add another second stage:
Find many great new & used options and get the best deals for Scubapro Atemregler zweite stufe G 260 at the best online prices at eBay! Free shipping for many products!
www.ebay.com
If you contact the seller, it probably can assemble a setup for you with a long hose and perhaps also an SPG, with some discount for the combined purchase.