You must have a real expert installer if he is willing to try and install full sheet vinyl. The sheet has to extend under the slides, good luck with that. Look at all the little cuts/angles.
I am not an expert, have done small area's of vinyl, I didn't even consider it when I redid my flooring.
Are your slides flat floor or do they slide above the existing floor.
I installed LVP type flooring ~16 months ago. I had a soft spot in the floor in the front (still trying to figure out how/where it came from but this is where my wife keeps her dog crates and I think it was from years of them spilling the water dish). Here is a link so show you what it involved. https://www.irv2.com/forums/f115/new...ks-564571.html
Yes it took a while, lots of fitting. My 2 slides are raised. The bedroom slide had 2 rollers mounted at the foot of the bed and the bed frame actually rides on the rollers. I removed the whole thing to put new flooring down. Glad I did, found the rollers digging into the bottom of the bed frame. Put strips of metal to protect. The rollers do have a height adjustment.
Front LR slide has 4 rollers, two of them mount on the bottom of the kitchen cabinets and roll across the tile floor and 2 rollers mount in the floor and the slide rolls on these. The rollers can be adjusted.
I opted for the LVP because it was a DYI project, I had plenty of time. I bought the LVP from Lowes, this was the best Pergo they had with a "lifetime" warranty. It was about the same thickness as the laminate flooring I had installed 11 years prior. The Laminate actually held up really well. I found the LVP easier to cut, slightly harder to install. I was parked in my garage with my inside shop right there with all the tools I needed.