I don't really think you need much help. Perhaps lead-wyrhta might be better than lead-gota for plumber but lead-gota has the advantage of being listed in Bosworth&Toller (as a 'lead-founder'). Just being picky really - a founder seems to me to imply someone working in a foundry rather than out and about as a plumber?
If what you are looking for is the unpredictable element of 'drift' or 'slide', have you looked at 'wandrian', 'wandlung' and 'wendan' which incorporate many meanings of 'shift' (ed..,oþ-....,.....)?
As for the concept of 'time', it all depends upon the context. Since you mentioned a calendar, you may be looking for precision? The following list of terms other than 'tima' and 'tid' may help (or not):-
byre - a time, a season, an event...
cerr/cyrr - a turn, a time......
f æc/fec - interval of time
fierst/first/fyrst - an interval of time (appears more measured than fæc?)
hand-hwil - a moment
hwil - a while, a space of time
hwil-fæc - a space of time
hwil-stycce - short piece of time
hwil-þrag - a space of time
ild - an age, an era, a period of time
sæl - a time, an occasion
stefn - a fixed time, a turn
stund - a while, a time, an hour
tæl-mearc - a date
þrag - a time, a season
Incidentally, Harry Ball wrote a great article on the calendar and measurement of time which used to be on the old web-site. I don't know whether this might be rediscovered somewhere?