Interesting findings here..
At-failure set with light weights before your regular sets: more muscle strength, more muscle mass
https://www.ergo-log.com/at-failure-set- ... -mass.html
They used 20% of their 1RM and trained to failure, rested 30 seconds and THEM performed their work sets. I'd try this, if not for the fact it'd take a LONG time to reach failure, with 20% of your 1RM!