Quotes from Eddie Kantar

You may discover an easier way of counting, but for most people the subtraction-by-two method works just fine. If you just have to be different, here

Whenever you hold a three-card sequence or longer at the head of your suit you always lead the top card of the sequence. The top of a sequence rule takes precedence over the fourth-highest rule.

TIP: When holding two long suits, one of which contains a sequence, you should lead the suit with the sequence.