queries switching from MH-E to notmuch

[Stephen Eglen <S.J.Eglen@damtp.cam.ac.uk>]

[Apologies if this has gone through more than once, I've been having
problems subscribing.]

I'd like to switching emacs mailers, from MH-E to notmuch, as I need a
mailer with decent IMAP support.  Compared to gnus, notmuch (with
offlineimap) seems much quicker, and I like the sound of tags + fast
searching.  Can anyone help with the following points:

1. Deleting emails 

I've seen the suggestions on the emacstips for  keybindings to bind 'd'
to adding deleted tags.  But how do you then delete the mails from
the local Maildir (and then for offlineimap to propagate back the
deletions to the remote imap server)?  Do you run cron jobs to do this?

2. viewing both the search results and current thread

I'm used to the MH-E (and VM) idea that when browsing a folder (or, here,
search results) the top window shows the subject lines, and the bottom,
larger, window shows the current message.  e.g. see the top screenshot
at: http://mh-e.sourceforge.net/screenshots/.  As you scroll through the
folder contents at the top, the bottom window shows the corresponding message.

By contrast, in notmuch it seems that you either see just the search
results, or one thread, but not both.  Would it be feasible to get
something more like the behaviour of VM and MH-E?  I can write elisp
fluently, but before I look into it, I thought I'd check to see whether
this is feasible.  (I've just seen that this is the bottom item on Keith
P's wish list: http://keithp.com/notmuch/)

Thanks,
Stephen