Goto Projector Central. Look up throw distance.
I've done a fair amount of research. Lcos is best.
JVCs have better contrast and 1900 lumens. Don't know about their newest models other than some of them have 8k. I was going to get an NX5 but it couldn't quite do 120 inches in my room. Lens memory.
Sonys have relatively low input lag at 30 ms (for gaming) , reality creation (good for gaming too), a slightly wider lens than the JVC. It may be best to get a projector from a dealer. Shop around. I got my 295 es for 3400 on Amazon warehouse. Downsides are 6000-10000 to 1 contrast and 1500 lumens output for the 295. I think the 325 may be the same except for improved tone mapping. The 695 is brighter and has an iris and lens memory. I literally had to go into secret menus and make a number of changes to the 295 es until I was satisfied enough with the picture to keep it.
I think the 695 es or an NX5, or whatever the new model is may be best for the size and distance of your room.
TLS is right, center speakers suck. But you may need one to get the screen closer to eye level. IIRC you want the bottom 1/3 of the screen to be at eye level. Getting the screen to the right height is the only legit reason not go with a real speaker. An SVS ultra bookshelf is better by far than an SVS Ultra Center. Also don't mix and match the Left Center Right channels, get the same brand and speaker line for LCR.
I am experimenting with a Vertex 2 and panny 820 tomorrow. Essentially the vertex 2 spoofs the edid to allow a projector to display Dolby Vision. LLDV is done on the player and not the TV now, so the vertex 2 tricks the player into sending a DV signal. The player to get is the Sony X800 m2. Lots of 2019 posts will say to get the Panasonic, and that is a good player for projectors, but it cant force Dolby Vision like the X800m2. I haven't used it, but apparently this combination can force Dolby vision on everything. According to reputable dudes on other forums, the vertex 2 is a must have for projector owners.
And why is this important? Because HDR disc's are often mastered at say 4000 nits. An average 4k HDR TV is going to do like 600 nits. DV knows this and adjusts the image to the capabilities of your TV. A bright TV can do like 1500 nits last I checked. Projectors are capable of a whopping 150 nits or so. So getting HDR to work well on a projector is tough. The Panasonic 820 has specific settings for projectors and HDR. But I'll let you know if this vertex 2 is really the game changer people say it is.
I should mention that the 295es projectors is plenty bright for SDR blue rays. HDR is where the struggle is for all projectors.
Screen size is constrained by your wall size and projector throw. With that said, I wanted 40+ degrees. I researched a lot and 40ish degrees is the like being in the center of the theater.
Viewing Distance Calculator
www.hometheaterengineering.com
I have a motorized screen because I have a TV behind. If this is a dedicated HT, and not a living room, I see no reason for a retractable screen.
Once you've nailed the size of screen based on viewing angle. Pick a projector and look at the throw distance calculator on projector central, scroll down and see if you will have enough light based on the screen size and distance.The screen can also aid your brightness. Some screens reflect more light which is referred to as screen gain. I should ask if you want 16x9 or a 2.35:1 screen.
Also projectors lose brightness over time, and their bulbs must be replaced. Some projectors have lasers which last 10 times as long, but they're expensive.
There are some really, really bright projectors out there. But theyre DLP. Spinning color wheels. E shift 4k. Crappy contrast. Not all super bright projectors are crappy, but you may not need that extra brightness at the expensive of deep blacks that would get from a JVC.
Projectors also function as space heaters.
I wrote this on my phone. Sorry for any errors.