Perhaps having the chamber coated with materials and at temperatures where the H(0) produced is not superfluid could help:
https://doi.org/10.1063/1.4947276
Polymer and amorphous-material barriers also seem to work towards constricting/limiting superfluid H(0) flow along selected areas:
https://aip.scitation.org/doi/10.1063/1.4729078
Their usage was also discussed in Holmlid's patent applications.
https://patents.google.com/patent/EP2680271A1/en
https://patents.google.com/patent/WO2018093312A1/en
However it's not clear to me if to produce the non-superfluid H(0) one needs it to be at least initially in a superfluid form, or in other words if conditions which would prevent superfluid H(0) to form would prevent all types of H(0) from forming at all. There appears to be such suggestion in the general review posted last year.
https://iopscience.iop.org/article/10.1088/1402-4896/ab1276
QuoteA magnetic field stronger than 0.05 T prevents the formation of H(0) (Andersson et al 2012). Thus the formation of the chain clusters is inhibited by the magnetic field. Since these clusters possibly are involved in the formation of the small clusters H3(0) and H4(0), the density of small clusters may also decrease strongly in a magnetic field.
(the chain clusters are the superfluid ones)