The plastic film I use will stay attached without glue and is removable. On some tanks I remove it every year or so to clean off the salt creap that manages to get between the film and the tank, it cleans easily in the sink and a final hot water soak makes it relatively easy to put back on the tank cleanly. There will be air pockets that will always show but I don't notice them.
This is the comany I use. You may want to call them to be able to order by the yard as that offering is no longer on the website but I suspect can still be purchased if their 32" x 35" standard size won't work.
New acrylic or Glass tanks are human choices and have no impact on the animals. As with any "choices" there are pros and cons to either. Acrylic weighs much less when you are looking at larger tanks but the weight is not as important for smaller ones (20 - 50 gallons). Acrylic is easier to drill, virtually never leaks (unless improperly sealed but this usually shows up immediately) even over many, many years where the silicone (especially on a tank that gets a lot of cleaning around the silicone) on a glass tank often has to be replaced after about 10 years. Acrylic can take more of an impact and is less likely to crack if hit. Both will scratch but acrylic does not take much (especially the newer acrylics that are not supposed to
yellow. IMO, this is a sales pitch for acrylic that scratches far more easily
) and will be scratched from the inside just from moving your rock around and routine cleaning even with the requsite acrylic scrapers (the outside is far less of a problem but tends to be harder to look clean). Scrached glass cannot be repaired, scratched acrylic can be but the required kits are costly (around $65) and the amount of work is extensive to bring the acrylic back to a "like new" condition (requires tank draining if on the inside). Glass is far superior for photography. I have both. For sumps, I prefer acrylic hands down and have converted my older tanks for this use when I have upsized but am mixed about my feelings for smaller display tanks. Most of mine are acrylic but the glass ones are easier to clean (except around the silicone, a seamless tank - not really seamless but is molded on three sides so there is no silicone toward the front - is my definite preference). Acrylic is far more expensive than glass.
I keep octos and not cuttles (for now anyway) so I have no direct sizing experience. From prior comments, I belive a 40 tall will be pushing the limits of aggression if you have more than one in that sized tank but hopefully our keepers will give direct advice.