Even the 2hp 'Picnic Basket' (their 'Flagship Lunchbox') is presented with blank panels between modules. And they often do their public demonstrations with these spacers.
https://www.twohp.com/systems/picnic-basket
So the first and best suggestion will be to buy some blank panels (1 or 2HP), really. Not very exiting but much more comfortable.
A small-format macro oscillator like Twin Waves or Beehive (a 8HP clone of Plaits) would be welcome in a small box to complete your Threshold.
Finally I’ll add an attenuverter/attenuator, and probably remove Jam Jam since you have Pam’s.
'On ne devrait jamais quitter Montauban' (Fernand Naudin).