Racking a slurry from one carboy to the next?

Hello, I'm not sure whether the question I'm about to ask is genius or if I should dig the ol' dunce cap out from storage.

I have 5 gal carboys, and I'm getting 6 gal carboys in the mail. I'm making a 5 gal recipe using WLP550 Belgian Yeast, which requires a lot of headspace. I already made a beer in a 5g carboy using said yeast and want to reuse the slurry. However, after seeing how much beer I lost due to headspace, I'd rather ferment it in this upcoming 6g carboy by using the same yeast. So obviously I could yeast wash and make a starter, but... the slurry is healthy and the style is similar. If I weren't so concerned with headspace I'd just reuse the 5g carboy, but since I've got this here 6g carboy, I'd rather use that.

I have a funnel... can I just rinse the slurry with pasteurized beer or RO water and then funnel it into this new 6g carboy, or is something going to prevent that from working out? And since the slurry is obviously viable, do I even need to bother washing, just pitch in as much free slurry that pours out of my carboy without washing?

Surprisingly or unsurprisingly, this question appears not to have been asked yet.

It has been asked, and yes you can do that but you will be transferring all the trub from that last batch along with it.
Washing the yeast is really rather easy and doesn't take long, and you can store part of it for future projects.

You can pitch directly from 1 fermenter to another. No problem at all.

The only "But" is that you want to pitch an appropriate amount of yeast for the next beer. Unless you are making a monster brew, you wouldn't need the whole yeast cake.

Going to be a ~1065OG beer finishing at ~6.5%, was thinking of just trying to get as much of the cake to come out into the new fermenter... half of the slurry? Is that good?

Yeast population is really something I lack know-how on.

just pour about 1/4 or so of the slurry into the new carboy ( of course sanitized) and brew on....

Perfect, thank you for the reply.