RYAN - I read you old post, hyd. remotes are always in pairs, by Four remotes do you mean for pair or just two pair? If your just feeding the circuit with the charge pump of the hydro unit the Pioneer 4000 series quick-connects, 3/8" NPT threads are plenty. And 3/8" hose in O-K too. They're cheap, almost as cheap as the 1/2" versions which are on hundreds of thousands of ag tractors. The 3/4" versions are only used on really HUGE circuits to run things powered by high speed or high torque hyd. motors on the latest ag equip. And they come at a hefty price. Plus the smaller hose has a higher pressure rating, tighter bend radius, and it's cheaper.
If you want more info, check Northern Tools' Master catalog, and maybe their website. Gives you an idea of cost, flow & pressure.
Depending on what all you end up deciding you want to run with your hydraulics, you may want to install a separate pump & reservoir. It would give you more flow volume, pressure, wouldn't be effected by tractor movement. The added pressure gives you much more hyd. power in a smaller space, and lower cost overall.