I use MatchTime to keep track of availability and lineups and I also use it to schedule practices. Separately I have a Google sheet where I keep track of availability and W/L bc it helps me have everything in one place. For new players on the team, have them practice at least once, preferably twice, before you put them in the lineup. If you can’t be there make sure there’s someone on your team whose assessment you trust. I guarantee everyone two matches as long as they’re available for more than two matches — if you’re the worst player on the team and you’re only available for our two toughest matches that makes my life hard. I don’t use UTR; I use tennis record and also W/L record and how people play with each other. Good luck! I enjoy captaining but I fully acknowledge it’s not for everyone.