How Will The 1961 Towers Work In My Surround Setup?

The short answer: Excellent!

The longer answer:

The 1961 Tower is a versatile speaker that can fit almost anywhere: Both physically and sonically. It delivers a dynamic sound with tons of impact thanks to its four 5,5" woofers. It will also deliver a wide soundstage with a good off-axis response thanks to the waveguided tweeter.

It might have smaller woofers compared to the 1723 monitors, but because it has twice the amount and a different cabinet: The dynamics and impact are surprisingly comparable between the two.

What applications are the 1961 towers suited for?

They are most commonly used as front speakers in surround setups, which is exactly what they are designed for. If you have the space for it, it will work amazing as a center speaker as well; especially behind an acoustically transparent screen.
A use case many people don't consider is using them as rear surround speakers. If you are in a room where the rear wall is too far away to properly utilize one of our surround speakers, the 1961 tower will be an excellent choice without the need for a stand.
You could even build a complete 5.1 surround setup, consisting solely of 1961 towers. Having identical speakers all the way around will bring the surround experience to a completely different level.