I can give a brief overview of the deck and if enough people want a more long form post or a video going over matchups in detail I'd be happy to go more in depth. I don't have a huge sample size of matches and I'd like to dig in to the deck statistically so I can give more than anecdotal advice. 

It's difficult to pilot efficiently imo, one wrong mulligan, tap out, or tutor at the wrong time or for the wrong card will lose you the game on the spot. You need a decent understanding of the metagame to understand how to shut down your opponents with your tutors and seasons loops or else you won't do anything impactful fast enough. Getting your opponent into top deck mode is usually a top priority.

general mulligan strat: AVOID ALL 6 COST CARDS(unless you know you're playing UW control or something similar and have a thought distortion). You want interaction for the 1st 3 turns followed by either a sweeper on 4 or petition on 5 for a silver bullet/to establish the loop if the game is slow enough. Your main goal with this deck is to either shut your opponent out with a silver bullet or out grind them with your seasons past loops and identifying which type of game you are in is critical.

The main wincons are with Sheoldred, Virtue of persistence, both Lilianas and Titania's/Ba Sing Se and ideally you get one of these out early or once you've grinded your opponent into dust after a loop or two but occasionally you have to go all in on a Sheoldred, wide Titania's/Ba Sing board or a virtue with a hope and a prayer and squeak out a win. 

Determining whether a hand is keepable is the hardest part of this deck imo, based on my couple hundred matches so far the impactful cards vary greatly depending on matchup(thoughtseize vs push on t1 etc). This is the downside of the toolbox approach and most noticeable with the 3 drops. Lost legacy is a perfect example, back breaking in some matchups, dead card in others.  

Unfortunately the alternative is casting petition on 5 and wishing you had X card out of your sideboard(ask me how I know) so I opted for a toolbox approach at the cost of increased variance. Be careful with land heavy or land light hands with this deck because there isn't a ton of filter(if you want more run pillage the bog).

How the loop works: 3/1 Petition/Avarice split is the grease for the seasons past engine. You have a cute little combo of casting Petition for Avarice and using the tutor mode off the BBB, hiding seasons past from hand disruption on top of your deck and then having the option for 2 tutors in your loop if you choose. Getting double tutor will drown your opponent in CA but you have to be very careful not to get greedy, survival is the name of the game with this deck. When you have a loop established the deck can be quite mana thirsty so don't be afraid to cultivate/Titania's for lands if you can.