K04 install - Coolant drain required/recommended?

I tried to google a lot and ask in various threads without any clear answers.

Do we have to drain the coolant completely through the coolant line connected to the turbo or just top up what has been drained from disconnecting the hose and block it off while it's off the IHI?

I bought a 1.5L G13 from the dealer and any info with this is appreciated. This part of the install is blurry to me.

Stuff I learned about coolant in our cars (my write up):

1- Buy G13 coolant from Q-auto for the top-up, don't use any other brand (G13 replaces the old G12 and both are safe to be mixed in your cooling system)

2- Check coolant when car is cold only and it sound be between MIX and MAX...a little bit over MAX is fine.

3- Never use tap water (normal water) to top-up coolant, sure our parents always did it, but on the long run the salts and bacteria in the water can eat up the metals in the cooling system.

4- G13 is mixed with distilled water, ratio of 1:1 is recommended, but you really can add more water than G13, since it never gets cold here at all

5- G13 CAN be used on its own for little top-up..but it's best to mix it as explained in previous step.

6- Coolant flush isn't necessary (According to VW)...keep an eye on the coolant (in the expansion tank)..if it turns from good pink to bad orange or brown or you see black particles in tank..it means that you need a coolant flush.

7- Coolant flush is performed by disconnecting a cooling hose near the oil pan after jacking up the car...coolant will drain out...then tank filled with distilled water to clear any contamination...then fill with G13& distilled water 1:1 mix....very easy process that can be done at home.

Looks like I will do this:

1. Drain all coolant
2. Remove IHI
3. Fill with distilled water while draining from other side
4. Install K04
5. Fill with 2:3 (G13:distilled water) mixture

How does this sound?