I seem to recall there's a key combo (like Shift, something, Select) that will open up another bank of 16 user performances on the MX61

I'm not familiar with that instrument so you may need to wait for a definitive reply from others.

But a review of the manual indicates that there are 128 preset performances and you can create upto 128 user performances.

You can find the manuals here:
https://usa.yamaha.com/products/music_production/synthesizers/mx_bk_bu/downloads.html

This info from the top of page 21 may be of help

NOTE The 128 Performances are divided into eight groups (A– H), each of which consist of sixteen Performances. To select these groups of Performances, simultaneously
hold down [SHIFT] and use the [DATA] dial or [INC/
YES]/[DEC/NO] buttons.

That sounds like on the MX they have 8 pages of 16 performances each and you have to use that above tip to select the page you want and then a number from 1 to 16 on that page perhaps.

The appendix on page 35 has a 'Shift Function List' but it doesn't include what you ask about.

If the above doesn't help you will need to wait for someone with experience on that instrument to help you.

That works! Thanks, Andrew.