I used to use a mash pad, just like pictured in the grainger link. Worked GREAT!
I have since gotten used to mashing without a mash pad, I use a stainless steel false bottom, resists floating and letting grain underneath it. I run off about gallon or so to set the grain bed and then just run off from there. The extra 10-15 minutes of run-off is not an issue.
Try the pad and see if it works for you.
If you do, be sure you clean the pad
Very Well after use. Any residule sugars on it will encourage mold growth within the pad. Keep it clean and 1 pad will last a long time.
If you have a janitorial supply place near you, try them first. Several grades are available, not sure which is best?

but you will need to trim it to fit your mash vessel, and to fit your drain tube thru from your false bottom. They will cut with a scissors.
Good Luck!
Tom