I read somewhere that the habitual is traditionally wrong after má, or rather that the future is actually allowed, so má thiocfaidh is correct. Is this so?

It's vise versa:

má theagann tú amáireach, beidh Cáit sásta etc.

Yeah, Peter is right. You can't use the future after má : have to use the present habitual instead.

The present habitual is usual after 'má' but the future is not impossible. I quote from Cormac Ó Cadhlaigh, 'Gnás na Gaedhilge':

quote:

... nuair is í an aimsir fháistineach a húsáidtear sa chás san taréis 'má', ní foláir nó deintear scéal deimhin de nach baoghal ná gur deimhnitheach gan aon amhras an gníomh do dhéanamh nó na dála bheith ar chuma áirithe taréis uair na cainte do rádh. Mar seo, féach:
'Tá mé ag tabhairt cuireadh duit 'un na bainise má bheidh tú ar lóistín i dteach ar bith i n-aice leis an áit.'

Here's another question: using 'happened' with the conditional., example:

You would cry too if it had happened to you:

bheifeá ag caoineadh dá...

How does one use the 'generic action' of tharla if it does not fully inflect?