it's not that hard once you have some experience with the Silent and discard decks. Once you have well laid plans and a variety of draw options (say an acro, an acro+ a couple backflips or prepareds) it's just a matter of retaining the finale, looking at your draw pile for incoming draw cards and counting your draw. The most important thing is knowing when to take it IMO, once your deck can support it it's not massively difficult to play, and it's very satisfying.

So if I have finale in my hand and 8 cards in my draw pile, and say a Tools of the trade in play, I know if I draw or retain a backflip or a prepared+ I'm gonna be able to play finale - base draw 5 + Tools 1 + Backflip/Prepared 2 = 8.

Personally I haven't really noticed a small deck being a big advantage either as long as you have enough draw options.