This is a followup question to "What Hit Dice do multiclass characters spend at the end of a short rest?".
Under the rules for Short Rest (PHB p. 186, or here in the basic rules):
A character can spend one or more Hit Dice at the end of a short rest, up to the characters maximum number of Hit Dice, which is equal to the character's level. For each Hit Die spent in this way, the player rolls the die and adds the characters Constitution modifier to it. The character regains hit points equal to the total.
I have a multiclass character - level 1 Monk (d8 Hit Die), levels 2 - 4 Wizard (d6 Hit Die). At the end of a short rest I can spend up to 1d8 and 3d6 Hit Dice to regain hit points.
Can I spend the dice from my pool in any order? Or do I have to spend them in the order that I got my class levels - so always a d8 first, then the d4's?