Results are presented for a simulation carried out to test the precision with which a detector design (HERON) based on a superfluid helium target material should be able to measure the solar pp and Be7 fluxes. It is found that precisions of +/- 1.68% and +/- 2.97% for pp and Be7 fluxes, respectively, should be achievable in a 5-year data sample. The physics motivation to aim for these precisions is outlined as are the detector design, the methods used in the simulation and sensitivity to solar orbit eccentricity.