I don't know why you think 20 reps at a 10 rep max is a good idea for a novice.
Quote from Mark Rippetoe's Starting Strength on why beginners especially need more than one work set. "One school of thought holds that one work set, if
done at a high enough intensity, is sufficient to stimulate muscular growth. For novices, several problems with this approach immediately present themselves. First, inexperienced trainees do not yet know how to produce maximum intensity under the bar, and will not know how for quite some time. Second, if they don' t know how to work at a very high intensity, more than one set will be necessary to provide sufficient stress to cause an adaptation to occur â?? one set will not
I know that nearly killing yourself in the gym sounds hardcore and fun, but do you really think that you can keep anywhere near acceptable form while trying to kill yourself with squats. Most people have a hard enough time doing a mildly challenging set of 8 squats with out form going to shit, just imaging how bad it,s going to be once you've pasted failure by 8 reps and you're about to pass out and your legs are burning worse than ever before.
Of course all that is purely hypothetical, most people are not going to be able to do 20 reps with their 10 rep max and there for not produce anywhere near the intensity required for a one set program to work