RE: Spare tire cover with a drawstring?
Had many over the years on different RV's, only one we've owned has had an excellent fit.
But the last two tire covers on other RV's...
I put in grommets (1/2 inch I think) and used "bungee rope" to get good fit. Think I got supplies at big box store under $20.00 And used a bit of old inter-tube for reinforcing material that cover was made of; about a 4x4 square
https://www.amazon.com/Shock-Cord-inch-Polyester-Commercial/dp/B078NB6WBQ/ref=asc_df_B078NB6WBQ/?tag=hyprod-20&linkCode=df0&hvadid=241941596583&hvpos=1o1&hvnetw=g&hvrand=9616941298126695004&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9033337&hvtargid=pla-628786755512&psc=1
https://www.amazon.com/Harbor-Tools-30037-Grommet-Installation/dp/B001TY8JH2/ref=asc_df_B001TY8JH2/?tag=hyprod-20&linkCode=df0&hvadid=194883046452&hvpos=1o9&hvnetw=g&hvrand=6522665728332429495&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9033330&hvtargid=pla-315239383593&psc=1