I would estimate about 15mins to find and copy an archideaconal will (best time - probably longer) + 20mins or so to find an episcopal will (the wills are not numbered) - this assumes that the staff are free to do your copying - in practice I would estimate nearer 30mins/copied will.
You will be very hard pushed to do much research in 2 days unless you have a list of items in advance.
Also copies are 80p /page from microfilm - come with plenty of money