We're busy later in the evening/day, it's best to come earlier.
この場合、次のような言い方ができますよ。
ーWe're busy later in the evening/day, it's best to come earlier.
「遅めの時間は混み合うので、早めに入店される方が良いですよ」
ーWe recommend customers arrive earlier rather than later.
「遅めより早めに来られることをお勧めします」
ご参考まで!