The question about Dorian saying he used "conventional" methods to "build up" is disingenuous contextual dropping.
The querent asked how Dorian trained in his first year or two of training. Rimjob strawmandered that, as he is wont to, either from sheer stupidity, lack of understanding English or his unbridled -- and highly curious -- utter hatred of anything that had anything to do with Mike "Meth-zer" (hurhur, how clever :/ ).
Did Mentzer buttfuck you or what, dude? You only post here about HIT, Mentzer and John Heart.
John's arms suck, but do you have a better build?
Waiting for your latest disrection 
Again, another getbigger who doesn't pay attention to the facts.
A lot of context gets taken out of Dorian Yates training methods. He did not use HIT. Rather he did pyramid sets...nothing radical about that...
Dorian in his teens did a mixture of weight lifting and martial arts. That is what built his foundation.
When he took up bodybuilding he did not do one set to failure he used conventional methods as is evident in his training journals. He did various methods such as pyramid sets, straight sets, reverse sets, drop sets. These are typical methods used by many bodybuilders over the decades. It's only later in his lifting career he stuck to pyramid sets shown in his blood and guts vid.
Example
Chest
Bench press 135x10 200x8 265x8 285x7 310x5 pyramid sets
Incline press 250x5 240x5 230x5 reverse sets
Incline flys 70x8 70x7 70x6 straight sets
Source: his 1985 to 1990 journal files
Yates even admitted on his own twitter account back in 2014 that he used traditional methods and not hit to build up
"AdamB
@Adambloor1984
7 Dec 2014
@Dorian_Yates
had you incorporated your HIT style of training at that stage? Or did you use the more traditional volume style?
Dorian Yates
@Dorian_Yates
7 Dec 2014
@Adambloor1984
traditional"
All this by Dorian himself. There has never been a successful hit only bodybuilder or athlete. Never.