Coldheart is 100% correct, if you have players that act like they are playing ITC 40k it will drag and the fun will get tossed out the window. APOC is all about showing off your collection, setting it on the table, and then taking it back off - maybe even putting it back on a couple more times (un-ending tide like stratagems).
With dozens of APOC games under my belt in multiple editions I've developed a method for long ranged 'support' units... if the owner wants them to support another commander (ie shoot at someone not opposite them on the table) then they hand off a card with the number of shots, strength, ap, damage off to the player "calling in the fire" (team mate on the table where the shots are landing) and they resolve it. This takes a little bit of prep work, but speeds things up A LOT and keeps players where they are supposed to be.
I bring my 9 basilisks, I set up 3 firing batteries, I have 3 3x5 cards, each card has 3 lines one for each vehicle that looks like this:
BS 4+ 5+ 6+ | HEAVY D6 | S9 | ap-2 | d3 D | roll 2d6 for shots and discard the lowest
I give away 3 guns at a time (you can do less but I'm old school), they shoot them as they see fit, the card is returned in the morale phase and I'll line through 4+ when a vehicle drops a bracket so the next time I give it away they know.
I do the same for each weapon on my titans, knights, deathstrikes and anything else that can fire long range and ignore LoS. I also make these type of cards for my fliers, i slide over and do the movement, but hand off the card to the supported commander. In this case I leave a 3x5 with toughness and save/invul to and the supported guy rolls those saves.