Online Scrabble Handicaps
You can record your matches - including handicaps, so that the winner is the winner - on our platform rankade. It's a free ranking system for sports and games, suitable for Chess, Go, Scrabble, and more. Rankade doesn't use Elo, but its algorithm (called ree algorithm), although more complex (here's a comparison), is similar to Elo if you play 1-on-1 matches only.