Before you start decide whether they will be top bee space or bottom bee space . Then mark you plans accordingly in red ink .
You'd not be the first person who made a cock-up & produced parts for both methods & only found out about it when you played with building the hives up . ( Guess how I know ?
)
Bottom bee space is supposed to lay you open to less chance of squashing the queen when reassembling the hive , plus it's marginally easier manipulating the frames ( apparently) .
If you like you can make a heavy crown board out of 3/4 marine ply & put 3" side walls on it ( don't forget the bottom bee space lip or routed in on the side walls .
Using dovetail joints & a waterproof glue as well as stainless steel screws should see it stay solid & water proof fir a good 10 years if you also give them several coats of bee friendly waterproof varnish .
On my first ten crown board feeder trays I used rubberised bitumen to seal them as I had a 20 litre drum of it . That was a very BIG MISTAKE ! The rubber was just about the best glue man ever made for about 15 months till it fully cured & dried off . They were un-useable till then .
To get the bees up to & back down from the syrup feed :-
In the middle of the crown board glue & screw in a 2 "x 2" x 2 & 1/8" high block of rough cut wood & when the glue is set bore it out down the middle right through the crown board too .
This not only makes a nice heavy crown board it means you can fill the tray in the top with syrup feed a gallon at a time from a plastic watering can .
or
If you have a lot of hives like I had , 12 volt pump it in from a 310 litre barrel with battery power supply mounted on a trailer .
Doing it like this with crown feeders & a syrup watering can or a pump set up means you're not upsetting the bees if you're feeding them in inclement weather or at night in the dark after work .
It also helps curb robbing so long as your lids are sturdy & well fitting .
If your skills are up to it ...frames dimensions on this site :-
dummies.com/home-garden/hobby-farming/beekeeping/cut-list-for-british-national-hive-deep-and-shallow-frames/