First time build questions?

[Bentini1uk]

I'm planning my first ever water cooled build:

lian li 011d XL
EKWB front panel distro plate
Slim 360 rads top and bottom
GPU waterblock

I have a couple of questions:
What is the best vertical GPU mount to allow possible clearance to have my bottom rad fittings at the back of the case? I know its gonna be super tight.

Are there any must have fittings that will assist in keeping the runs straight, baring in mind its my first time but i'd like as close to perfect as possible? Im pretty confident i can manage 90 and double 45 degree bends but would like to avouid anything too complex.

I am looking for a yellow preferably pastel coolant that i can leave in for ~12 months at a time. If this isnt possible could someone reccomend a nice yellow translucet coolant?

Where will be the best place to incorporate a drain valve as i understand its gonna be difficult due to a rad on the bottom of the case?

Thanks in advance

 

[MikeTimbers]

drains should be somewhere that can be on the "bottom". That means it could be on the "top" normally and you would invert the case if you needed to drain. If you can, the ideal is to have a drain at the lowest point and a fill at the highest. One way to do this at the top is to have a rad with multiple inlets (e.g. XSPC EX line). If you have one of those in the roof, it can be used for filling and then also for draining by attaching a soft-tube and tipping the case. It means you can hide the drain away from sight.