I should add that, back in the late 1970s and early 1980s, we used to wargame 633 Squadron in the scout hall where Harold Wood Wargamers used to meet.
The models were 1/72 Airfix kits mounted on three-foot high dowel rods which were marked off in inches for height levels. A clothes peg (U.S. clothes pin) stopped the models from slipping down the dowel.
Aircraft moves were 30 inches per turn (for a 300 mph attack speed) and the floor was chalked in one-foot squares and numbered. The German flak attacked certain squares each move at random and if you were in a target square THAT move there was a percentage die roll to determine a hit and then further rolls to determine aircraft damage.
I am currently looking at a table-top version of 633 using the Blood Red Skies 1/200 scale aircraft from Warlord flying on a hexagon gridded board. Six hexes per move at a rate of 50mph per hex.
There will be six height levels inside the Norwegian fiord with the fiord sides, mountains and rocky islands done in various thicknesses (heights) of 5mm foam board.
Flak guns varying from twin machine-guns, single 20mm, quad 20mm and single 37/40mm will be placed at points along the fiord to shoot at the Mossies. Thus the Mossies can also shoot back and try to knock out or suppress the guns on the way in, improving their chances.
The film's plot was just plain suicidal but the original book offers a greater chance with three Mossies dropping their bombs early and attacking the flak AHEAD or beside the lead bombers. The book also improved their chances by allowing the Mosquitoes to fly up a parallel fiord part way and then fly through an intervening valley and thus miss out half the fiord's guns. In the book the squadron leader thinks this will double the chances but he then wryly observes that "double zero is still nought".
Players can elect to fly high to put more distance between their aircraft and the flak but any aircraft ending a move at height levels 5 or 6 risk an attack from FW 190s. The 190s will not come lower than 5 due to the risk of being hit by their own guns.
Aircraft which survive to drop their earthquake bomb on the mountain and glacier exit the fiord and go into a holding pen at the far end for two moves to turn around and then re-enter. Once in the holding pen they run a two-move risk of being attacked by FW 190s. If they survive, they re-enter the fiord next to the target and now fly back down the fiord attacking flak pits and trying to support the other bombers still coming in (see the last film link above for that detail).
Damage on the mountain/glacier is accretional, probably three hits to begin rolling with a D6 die roll for each bomb hit after the first three on an improving scale.
A '6' on bomb four and an additional +1 for each hit after that. So bomb six has a '4,5,6' chance of destruction.
Flak hits on the aircraft will include aircraft damage, pilot wounds and 'flinch' reactions where aircraft can lurch one hex left or right as they are being hit. Of course this means that aircraft which flinch could also hit the fiord sides if they are too close.
I should mention that Harold Wood wargamers also did The Bridges of Toko-Ri in much the same manner but 633 Squadron was always the favourite.