I will simply repeat what I have read from multiple sources for rucking weights (whether it's coming from goruck.com, ruckformiles.com, MTI-mountain tactical institute, rucking.com etc) it sounds to me like the most common recommendation is to begin with about 10%-15% of your body weight and gradually increase until you're up to about 30%-35% of body weight. Pace is gonna be dependent on your current fitness level, but beginner recommendations are for 15-20 minutes per mile. Distance again depends on current fitness level, but if you're new the recommendation is 2-3 miles.

You'll do what you're gonna do, and rucking seems to attract an aggressive crowd(shocker, right), so when I used to try to pay attention to ruck groups on FB or reddit or anywhere on-line there was a never-ending stream of people posting their workouts and it was almost exclusively populated with people carrying max weights(often in excess of that 30% of BW recommendation) and going very fast for very long distances. That's fine if they are prepared for it, but I've got my doubts and I've seen too many excited beginners in all realms of fitness put themselves through workouts they aren't prepared for just so they can show off on-line. I got tired of the show offs and left all of those discussions.

Time and time again, when the knowledgeable people would chime in they would re-iterate how important it was to start lighter, start slower, start shorter, and progress slowly while paying close attention to the feedback your body is giving you. They reinforce the standards I gave above, but people do what they are gonna do and people love to do too much too soon. Stress fractures, tendon/ligament issues, and strained muscles don't always make themselves obvious right away. I've heard from too many people who thought they were doing well and were excited with their progress and their training and then woke up one day with a new pain and learned the hard way that they did too much, too soon and then had to back off for a while.

My recommendation would be to not get only a single 30lb plate to start, but I don't know exactly what gear you're using or what your baseline fitness is or body weight. Once I finally bought some official "ruck plates" I bought a 20lb and a 10lb, and I still have my barbell weight plates I started with, so I've got several 2.5lb, 5lb, 10lb, 25lb plates. I can load out with anywhere from 5.2lbs (that's what my empty ruck weighs) up to that recommended max of 35% of my BW, and I can do it in increments as small as a few pounds. This gives me great variability.

With a single 30lb plate you have no option but to ruck with 30lbs, but what will you do if you want to do a different workout? Perhaps a speed/hill workout with 10lbs? or 20? Ideally I think for a 200ish pound man, get a 10lb, 15lb and 20lb ruck plates. Just 3 plates, that's all to start, you could even skip the 10lb and just use water or sand to make a few 5 pounders to stuff in your ruck or carry with you if you want to use a plate carrier or vest.

That way you can mix and match and ruck with anything from approx. 10lbs up to about 45lbs if your plate carrier/ruck/vest can handle it. This gives you a variety of weight you can use for a variety of workouts. Also search online for tutorials on how to make your own weights with anything you want, water, sand, bricks/rocks, camping/survival gear, books, anything.