4 star ticket advice

I was originally going to take saberlot because I have managed to get “Another Ending CE”. Someone said to me that saberlot and li shuwen would benefit this. I won’t be taking li shuwen because I already have a Lv90 OG cu. But yesterday, while trying to roll for merlin (failed again), I have rolled for Salter. I’m an ftp player and the lack of assassins and zerkers on my team worries me. I have a Lv50 stheno, which I don’t know if useful, so I’m focusing more on evil wind. zerkers could be neglected because I could raise my lubu or kiyo to high level, after some time. They both of them were NP5 already too. My question is, should I push on saberlot or exchange my ticket for another servant.
BTW, here’s what I have.
Lv 83 jeanne. (haven’t maxed out yet, focusing on getting more sq to roll for merlin)
Lv 90 OG cu.
Lv 80 ishtar rider
Lv 80 nito
Lv 70 OG emiya
Lv 70 maid alter
Lv 60 xanzang
Lv 65 hans
Lv 60 kiyo
Lv 50 lubu
unleveled sr servants: stheno, salter

Kiyo is fine for farming (Spartacus is better, though)—have you considered Ibaraki? She’s in the general pool (so NP upgrades as possible) and she’s quite tanky, especially with Merlin and Mash/Hans. Great for story content and CQs.

Lu Bu is, actually, more of a farmer than anything else. He’s best when he’s nuking high-HP enemies in free quests.

Re:Saberlot—he has great Merlin synergy and he’s very self sufficient—he also doesn’t fulfill a similar role to Salter, who is a farmer. But we’re about to get Brave Liz, an ST Buster Saber welfare, who will outdamage Saberlot’s NP pretty handily. Her event drops Thursday so I’d read up on her/borrow her from your supports and see if she’ll be enough.

The 4* Assassins are pretty underwhelming. Wu is the standout for her immense steroids and rare quick support—she plays nicely with Riderin, too.