You might try 4'x6', landscape format. We typically start by centering the object around 5' above the floor. Might work better a little higher but you can try it out with tape.

to PirateFoxy I have NOT seen sofa bed options but, I have seen their sofas and they are FIRST CLASS all the way. They are upscale product and upscale for a reason. That reason is quality. I would trust an item made by American Leather but, you know its just in the nature of sofa/beds that they are notoriously NOT comfortable so, you might want to work on that "comfort" problem a little more. I know I have wrestled with it as well and finally just bought a "custom made" day bed from an architect/wood fabricator on www.etsy.com. Am waiting for it now! Will look for picture and attache for you and others to see. But, I can recommend American Leather (made in Texas) to everybody.

See this discussion for some great ideas https://www.houzz.com.au/discussions/help-i-bought-an-avocado-lounge-dsvw-vd~2879842?n=1

(overlapping posts but doesn't change suggestions especially need for locations of doors and windows) to make space for a 55" TV i would swap rooms and make a media room with a wall of cabinets to include the TV, music, books etc and have a roomier dining room with extra small lounge chairs that can be rearranged when you need seating for more than 4 to watch TV..the lounge could be a sofa bed with a storage coffee table for bedding but best size and placement of all furniture depends on measurements and you will use an accurate plan of the whole apartment (including exact size and location of all doors and windows for choosing furniture, floor and window coverings, appliances, built ins, kitchen cabinets etc etc so if you can make a rough plan showing the distance from the windows and doors to all corners i can make a more accurate plan for you