@aeonsovarius I've played with both Night's Whisper and Painful Truths in a Show and Tell variant. They work much better here because you are more likely to draw creatures and then have the ability to use Show and Tell to play them. If you draw more cards and you are not using Show and Tell then you will likely need two Jaces plus Chart a Course and maybe See Beyond. I prefer not to use the black draw spells anymore because they are not the best against Shops and have been sub par in other matches.
Show and Tell is a strong card, but I found myself losing to what my opponents would put in play. I actually had Show and Tell resolve against me in the last Vintage challenge. My opponent put in Griselbrand and I put in Leovold, Emissary of Trest. I took two hits from Griselbrand, and then I bounced it with Jace and won. I was actually playing Oath myself with Leovold as a side board card.
The counterspell package always contains Force of Will in this deck. I'm actually still testing theories about certain cards and what they do in certain matchups.
Gush does seem like an awkward card in Oath. I didn't play with it initially, but decided to play with it one day and went 5-0, so I kept using it and continued to put up results. I find this card to be vital to Oath's strategy. It is best used as a mana fixer rather than just something to draw cards with.
I think that Oath would be a fairly difficult deck to play as a first Vintage deck right now. It is probably more complex than it has ever been. I started playing it a long time ago when Tidespout Tyrant was the go-to creature. After that I left Magic until 2010 or 2011, and then played it off and on. After that I played various Oath builds until Brian Kelly created an Auriok Salvagers version using Ancient Grudge. At that time it was probably one of the best decks I had ever played. I eventually took several more brakes from Magic. When I came back I wasn't as successful with the Salvagers version, so I started using a Show and Tell version. I found that it was great for leagues and very poor for constructed tournaments. Oath has struggled as an archetype for quite a while now, but good players have found ways to win with it. Arlin Kord, Sphinx of the Final Word, Deep Analysis, and many other cards have been used, but they really change how the deck works. This makes the deck fairly difficult for an inexperienced person to play on MTGO because of how good the players are there. We have recently gotten new options in the form of Mission Briefing and Niv-Mizzet, Parun. As you can expect, the new options from the last couple of years can present some difficulty when looking for the correct mix.
Recently, I have found that three Preordains are great for creature based match ups because you can find the Oath more quickly. I replaced Ancient Grudge in the main deck with Fire//Ice. I don't really want to go into the details of Fire//Ice and why I play it over other cards, but it is good for cantripping and removing cards like JVP. I've written about Niv-Mizzet, Parun elsewhere on the site, so I won't go into detail about it here. Basically, this card can be hard to play with even for experienced players. I side it out quite often against creature decks. Arlin Kord is still effective, but it is not always effective. Having said that, most of the deck options are not always effective, so you must use your judgement when anticipating the meta you will play in.
I have been experimenting with Leovold and Kambal in the sideboard, and they have been very effective, I have recently cut back to two Pyroblasts because of how strong these cards are in certain matchups. They are great against Storm, PO, the version RWU Xerox that uses more JVP's and Fragmentize, and probably other decks. These are traditionally some of Oath's more difficult match ups, so I am really enjoying these cards. Leovold can be good in the mirror, but not always. I would say you almost have to feel this one out. As far as siding out Oaths in the mirror, the more experienced the opponent, the more Oath's I like to side out.
Sorcerous Spyglass is a card that I have started using again. It is really strong against Survival, JVP, and a variety of other cards. I am really enjoying the utility that it provides.
So, with all of these random thoughts and information, I would say that practicing with every version of Oath from the last four years is a good idea. It will allow you to see why certain cards are played, and when they are included. I would also say that there are many effective Oath strategies at the moment. This presents very interesting deck building opportunities, so I am interested in seeing what players come up with.