Should the letters of prolongation, Waaw and Yaa, be pronounced with tafkheem if the letter preceding them is pronounced with tafkheem?

The intonation (tajwid) scholars did not state that the three letters of prolongation (harf madd) are subject to tafkhim (velarization) except for the Alif. The Alif is velarized if it follows a velarized letter and is attenuated (tarqiq) if it follows an attenuated letter. As for the Waw and the Ya, there is no velarization for them because they are among the attenuated letters of istifal (lowering of the tongue), with the exception of the Laam and the Ra in some of their states.