I do not personally know Walter Eichorn, although I have friends who do.
I have been told (take this anonymous double-hearsay for what it is worth, i.e., not much) that Walter has an outsized ego. Assuming that to be the case, it doesn't necessarily follow that he wouldn't respond positively to a politely worded request for advice. In my experience, many people find it quite flattering to be asked for advice (as opposed to asked for actual assistance).
At any rate, as you already have time on the Chipmunk, you have made significant headway towards flying the heavier iron, and I don't think that it is unduly presumptuous of you to ask for advice regarding the next steps on the ladder ...
Good luck,
MLS-12D