Sounds like a good beginner league. Fantrax is great with salary cap leagues, their salaries are correct 99% of the time.
One big decision you need to make is if you're going to use cap hit, AAV or yearly salary. Fantrax allows you to use any of the three. As an example, I'll use the most recent signing from CapFriendly who is Kale Clague: https://www.capfriendly.com/players/kale-clague
- Cap hit: $792,500
- AAV: $925,000
- 2017-2018 salary: $767,500
Please notice that performance bonuses are much higher for high draft picks like Jesse Puljujarvi who has AAV of $3,425,000. So that decision has major effect on player values but I've played in different leagues and used all of the options, so all of them are just fine as long as everyone understands exactly which of them is used.