Thats the problem with WTO assist. It's an incomplete system but people crow about it because of cost. Its like buying a 4" lift kit that only contains coils and shocks. It works but much more is needed for a proper reliable set up. The PSC is priced too high imo but is a complete solution that just works.
Agreed, the PSC stuff is pricey but, like you said, it flat-out does the job.
First go-'round I bought a PSC 1.75" x 6.75" ram, ported my box, made hoses, burned on Synergy brackets, and plumbed a cooler and filter into the return line (pump and reservoir were stock).
The filter housing (Mr Gasket or similar remote housing for a common spin-on filter) leaked slightly
through a porous die casting that wasn't resin impregnated, and the factory pump didn't quite have enough pressure for my hydro assist or hydraulic winch.
Those problems pissed me off enough to open my wallet and add a PSC pump and reservoir / filter. So I ended up with PSC ram, pump, and filter/reservoir. 20/20 hindsight would lead me just take the hit and start with those components next time.
Now that the sting of price has faded, I have no regrets - everything just continues to work with no drama. Aftermarket parts that don't cost me time or worry are worth whatever I paid (especially since it's been years and I don't remember how much I paid
EDIT: Pump specs. need to be matched to steering ram diameter
(apologies if you already knew that)
I believe the WTOR ram is 1.5"
which works great with the factory pump's pressure / flow rate. The PSC pump I have matches well with a 1.75" diameter ram, but would make for twitchy / scary steering on-road with a 1.5" ram. I think you're just looking to play around with reservoir location, but I wanted to call out that potential problem if you were considering a different pump.