Summon on Caster Banner?

Do you have something called...EX luck? If not don't even try with that and you would probably end up with best caster Geronimo lol, but honestly no. Save for merlin

That's not enough to get a SSR servant, I got extremely lucky and got one of each with about 600 SQ. Saving up and waiting for a solo rate up is typically recommended for new or F2P players.

For these three SSR, you can wait for New Year Banner Guaranteed SSR class roll. 33% chance for either of these.
Merlin is unique because except this end of year, there will be no such rate-up for him.

depends on how much u need. I really needed 1 ssr caster for my team so I got lucky when I got 1 from 60 quartz

You could try but it might not be worth it. Due to how much you could summon. Last night, I got lucky and summoned Waver. So it could be worth it if you get a 5* Caster but be warned that you will most likely get a TON of 3*’s

The only notable SSR in this banner is Waver, since he's so good you can use him on anything.

Xuanzang is a ST offensive Caster and is usually negligible if you have a good SR/SSR Berserker or a good support.

Tamamo is irreplaceable in arts and stall teams, but she has a solo rate up on Halloween.

TL:DR: Not enough SQ, save for Merlin.