Forum adverts like this one are shown to any user who is not logged in. Join us by filling out a tiny 3 field form and you will get your own, free, dakka user account which gives a good range of benefits to you: No adverts like this in the forums anymore. Times and dates in your local timezone. Full tracking of what you have read so you can skip to your first unread post, easily see what has changed since you last logged in, and easily see what is new at a glance. Email notifications for threads you want to watch closely. Being a part of the oldest wargaming community on the net. If you are already a member then feel free to login now.

I have movement trays for skirmishers that have slots for models to stand in. Since
they will have to rank up when giving/receiving a charge will I have to get an empty
tray that's wide enough to hold the unit when skirmishing?

I believe so :-/. I also think your slots are likely not to be the correct distance apart. They need to look like this:

M = model
_ = 1/2" spacing

M_M_M_M_M_M_M
_______________
M_M_M_M_M_M_M

I believe they can reform freely when moving normally, so you might want to have the flexibility, anyway. But when they charge/receive a charge, the unit above would "compress" to make this unit:

MMMMMMM
MMMMMMM

And look just like a normal block. I'm just going to have a magnetized tray (I already make them and just need to make new sizes) without any slots. Doesn't look as cool, but for functionality with the new rules, it's what makes sense.

You have to remove them from the trays with slots under the current rules to put them into combat, anyway, though.

Looking back, from your wording it looks like you have the opposite problem (you have them ranked up, but would need to space them out for movement) but the result is the same- they're going to have to be able to go from 1/2" spacing side-to-side and front-to-back to a compressed block to get into combat.