#letsphysics

I'm confused as to how moving from the first main phase to the combat phase works. From what I've read, if I ask my opponent "Move to combat" or something to that effect, I have already passed priority to my opponent in the beginning of combat and do not receive priority again until they act or we move to declare attackers. How do I move to combat yet maintain priority before the declare attackers step? Say "move to end of Main"? Say that we're moving to combat but I'm holding priority?

I was playing a match at a GPT and the judge made a call that I'm hoping you can confirm for me: opponent casts Cryptic Command choosing to bounce my Pyromancer's Ascension and draw. He taps a Flooded Strand for the cost - I don't notice and he thought it was a Hallowed Fountain. After he draws, he notices the issue. He fetches, and shuffles. We call a judge because it changes the card he drew. The judge ruled that he should just fetch and take damage, putting no card back. Is this correct?

With respect to triggers and when they are "checked": Mizzix of the Izmagus is in play and a spell is cast that has CMC 3. Mizzix's controller has 2 experience counters. They put the trigger on the stack, and cast another spell with CMC 3. Because the first trigger hasn't resolved, another is put on the stack. It resolves, they now have 3 experience counters. Does the first trigger still resolve? Or are experience counters only checked to put it on the stack? How can you tell whena spell checks

A friend asked earlier and I didn't know how to answer: at an event like FNM, if you know the matchup, can you sideboard before it begins? Does this change for things like GPs?

Say I have a Glimmervoid and a Blinkmoth Nexus. I animate the Nexus and attack. It is now the only artifact I control. At end of turn, can I make the delayed trigger from the Glimmervoid resolve first so that I can keep both lands?

Regarding Brilliant Spectrum: it's 3U. Can X be five? "Converge - Draw X cards where X is the number of colors of mana spent to cast Brilliant Spectrum."

If I have an Arcbound Ravager, an animated Inkmoth Nexus, and a Signal Pest on the battlefield, and then I move to combat, declaring all three as attackers The opponent declares his blockers and as a response, I sack the Pest to the Ravager and then sack the Ravager to the Moth, does the Moth still get the Battle Cry buff?