Made a cut in carpet and the pad, and attached track directly to floor. Gave the track about 1/8" on each side, doors are only as wide as the track. no tack strip either and it is all good, even in walkway. use a little construction glue if needed.

Yes it cuts really easy with a regular 40-60 tooth blade on our chop saw. Its aluminum so it also cuts easy enough with a band saw, or locked in a good vice with a sawzall.

Very carefully - I picked the highest spot on the floor with a long level, put the track down, placed assembled door frame on track and used a cut off piece of track attached to the top of door with the floating plastic guide up about half way. This floor had a sag of about 3/4 inch in the middle and so i had to shim the bottom rail gradually and carefully underneath to meet the higher spots on both ends of the room. Alot of careful shimming with narrow PVC molding and construction adhesive on the floor, but it was worth it, the doors glide like magic. Same for the top, after leveling the bottom track, I put a door in the track and rolled it along and made adjustments to shim the board on the ceiling to be uniform with the door. I hung the top board with extra long screws so i had a gap to fill or reduce with shims so the top of the doors grey plastic glides were about halfway up in the top track ....

To Infiniti if you like, but the amount of space to hide would require a door for each, doors are available in approx 24", 30", 40" wide...

True, i watched Skyttas videos and blah ...