For now, all my Tweets will #crosspost to Mastodon, and Mastodon Toots will crosspost to Twitter. Likewise Retweets / Boosts

it's done via http://moa.party

join any Mastodon instance / server: they're all linked
#Twittermigration

for new Mastodon users .. the Fediverse (the way that Toots get shared across all the different mastodon instances) is a bit #laggy .. some of the bigger servers are very laggy. Likewise the crossposts between Twitter and Mastodon.
Be patient, there is a huge migration underway.
also .. you'l have to get back into the habit of using #hashtags .. Mastodon doesn't allow you to search simple text across the Fediverse - deliberately, to reduce muckraking / trolling / trollbots