Wa alaykum Salam,
Yes it is true, but without being rude, I do not think this is the place to ask such questions. People are very ignorant about these rules and the one you stated is not very known amongst either the Quran teachers or the reciters.
I think I wrote that in a post about a Shaykh before. I may have removed that post, it sounded too personal and I dont want people get wrong idea, If you want it back let me know..
That was just an example of the precision in teaching that Shaykh Ubaid Allah al Afghani in Masjid Nabawi (the Prophet's Mosque) taught, He had isnaad (chain of narration ) going back to the Prophet

and his knowledge of the Quran and its Tafsir was very great.
That was the way he would teach me, and it was very difficult!! He insisted that I practise reading infront of a mirror.
I dont think you should worry too much about that rule, I had to read like that and enforce many of the other rules including reading the Daal (which is in word Dhaleen) like a Zaal in (Zalimun) - this different to how 99% of reciters read. So, if people heard me recite that letter, they might think I am making a mistake!
But, the Shaykh insisted that everyone read like that because he had the evidence from the books of Tafsir and from the reciters of the past, and as he has proper Isnaad going back to the Prophet

so how could I not accept!
You do not need to read the waaw like that, as you have not been taught like that by someone who has the evidence and knowledge to teach you. Its like a rally driver or f1 driver being taught more precision compared to someone who is just wanting to drive. And Allah knows best.
You will need a proper Quran teacher though, if you are going to learn to read Quran according to the Tajweed. So, it starts with knowing exact pronounciation of each letter, where you should start where you should stop. Correct breathing, timing and so forth. The amount of proper reciters who have Isnaad and can read very very well you can count on your fingers. There are not many around, but, alhamdulilla they are teachers.
I recommend you try your best with whatever resources you can use. Use Quran Mp3 by Hosari, Manshawi, Abdul Baset Abdussamad, Hudhayfi,