My unsolicited advice for maximum return on investment, in regards to the sound quality of the resulting recordings?
Keep the 4061's and consider recording four channels. The improvement in moving to larger, higher quality DC polarized omnis (Schoeps, DPA, whatever) is real but relatively subtle unless in optimal recording situations with optimal mic'ing setups. In most somewhat compromised headworn situations, those differences will be more subtle. The improvement you can get by going to 4 channels with the intent of mixing to 2 is not subtle and can directly address problems inherent to the headworn recording technique.
Do that either by:
1) Adding a pair of forward facing miniature directional mics, placed coincident with the omnis. This allows you to either choose between either the forward facing directionals or the head baffled omnis outright, or to mix the two in various interesting ways. Mix them full range at various ratios and you gain mic pattern control varying between omni (baffled, outward facing) and cardioid or supercardioid forward facing. Not simply one pattern or the other but fine-tunable to any combination pattern in between, after the fact, by ear to whatever sounds best. You can gain even more control by EQing each differently before mixing them to gain control over pattern by frequency.
That gives you not only the ability to reduce some of the annoyance of people behind without completely sacrificing the naturalness of omnis, but also the capability of improving on the omnis alone even in an otherwise perfect situation, and more so than switching to higher quality omnis.
2) Adding a second pair of non-coincident baffled omnis facing forward and backwards PM me for details.
Which is more appropriate depends on the music and venues in which you record. Either approach offers very real, practical, non-subtle potential quality improvements, but requires increased complication of both the recording setup and the resulting mixdown work. IME, that is a larger barrier to going this route than cost (either to do this 4 channel thing or to move to a top-shelf omni pair), yet the potential reward is far greater as well, especially in a practical real-world sense.