2nd FTTC line for load balancing - crosstalk?

Hi,

I currently have a max sync 79987/19999 FTTC line with 8.6dB downstream SNR, so some margin there.

If I were to get a 2nd line installed for bonding/load balancing, how badly would I be hit by crosstalk?

Do I have enough margin that I should keep my 80/20 sync or would I be looking at more like 60/20?

For some there is no impact for others they have seen 10 Meg or so impact. Very hard to predict

Until recently I balanced 3 FTTC lines. (I now only balance 2). When 2 lines were balanced I did not notice any impact at all, but when I balanced 3 lines I had a 25 meg impact.