Attaching the bottom heater hose while the garden hose is still flowing into the top, then attaching the top hose, will be the best way of keeping as much air out as possible.
Also, you can bleed the air out of the system with a 10mm wrench and maybe a minute at most. There's a brass bleeder screw on top of the thermostat housing, with the engine running and warmed up, open the top screw slightly until you see bubbles, then close it when the bubbles stop and just coolant starts to flow out. You can repeat this process multiple times until the gurgling stops, my gurgling was gone after doing it once.
