I remember seeing a site which had a table, dictating how many X water volume should pass through the skimmer depending on the setup
If I remember correctly, it was none to 2x for a full reef setup, 3-4x for a fowlr
and 5+ for fish only or fowlr
with heavy bioload.
so your 29 gallon going by that table would be 90 to 150 gph
... I think a mag 2 would work well for you - after the head pressure from the skimmer, you'd be left with ~160 gph
i'll continue searching for the site and post the link when I find it.