Flaked Wheat and Oats

I am making my first Wit this week and it's calling for 4.5 lbs. of flaked wheat and 1 lb. flaked oats---making up 56% of the grain bill. Being that I don't have any rice hulls (and can't get any in time) I am concerned about the dreaded stuck sparge. Is there another method anyone can share to avoid this?

A few ideas I had:
1. leave the wheat and oats in a bag within the mash---I make my mash fairly thin
2. Mash them in a pot on the stove alone and pour the results into the beginning of the boil through a strainer

Any tips would be great!

With that large a volume of flaked wheat & oats I'd suggest postponing your brew day until you can get a supply of rice hulls.
Splitting your grain into two separate mashes leaves you open to a lot of uneven & uncontrollable variables (temp, extraction, etc) in either or both of the two not to mention a lot of extra work.
How far away is a brew shop that might have the rice hulls?
Didn't your recipe call for rice hulls?

What do you mash in? You can fit 10# of grain in a 5 gal paint strainer bag inside your mlt, but would work best in a 5gal Rubbermaid cooler. You need the diastatic power of a base malt to convert the flaked stuff, probably 2#, so by the time you did a separate stove top mash you would have done almost the entire mash that way. Are you milling your own malt? If so look at conditioning it first. It keeps the hulls intact and makes for a better filter bed, but bottom line brother--lots o wheat/oats/rye/flaked anything needs some rice hulls!

Recently I brewed a Irish Stout that had 3lbs of flaked barley (25% of the bill), and was out of rice hulls. I did a BIAB/Mash in a bag setup. Lined my mash tun with a large mesh bag (the ones used for BIAB), mashed/and sparged as if I was doing a normal AG mash. Worked quite well and made cleaning the mash tun a lot easier.

You might just go ahead and try it. I routinely do 50% wheat or rye, and dont have a problem on my system.