What tonearm and cartridge for Avid Sequel TT?

Most of the AVID TTs I have seen have often had SME arms so there is presumably some synergy there but that is only anecdotal. As for cartridges, that is more a matter of personal preference and what phono stage you plan on using in your TT set-up. What phono will you be using and what is your budget for tonearm and cart?

probably Pulsus, approx 3k

On mine I have an SME 4 with a Clearaudio Concerto. Great turnatable combining best of suspended and non suspended TT attributes, plus very easy to setup (including SME as well)

That's a really fine turntable! I have a Volvere SP with a SME IV.Vi arm and a Benz Ruby Z cartridge. Phono amp is a Art Audio Vinyl One.

I'm curious about your table improvement decision -- it appears to be like trading-in a 1950 Chevy for a 2012 Maserati Quattroporte. You might want to start your vinyl rebirth with less acceleration. I'm not trying to be critical, just helpful.

P.S. make sure you have tubes somewhere in your amplification chain.