Since a few weeks i am looking in to bond spreads and butterfly spreads to hopefully increase my profitability.

So far i find it very interesting but i keep struggling with the correct multiplier.
To be clear, i am trading ZN and ZB, not the spreads, i watch the spreads to get my entry's more accurate.

The multipliers i use for spreads are the multipliers listed on the CME website
https://www.cmegroup.com/trading/interest-rates/files/ics-ratios-2017-06.pdf

So here is the first question, what is the best spread to watch when i want to trade ZN or ZB?
Is it 3-1 ZN-ZB or is it 1-1 ZN-ZB. Or 3-2 ZF-ZN or 1-1 ZN-ZF?

Second question is what multipliers should i use to make butterfly spreads?
It looks like a lot of the information i am finding online is only making it more complicated since i see different multipliers/spreads.