It depends on the situation: if I can split the salary, then I would probably get something like 30-35% in bitcoin and 65-70% fiat, that because to pay the day-to-day expenses fiat is easier to use. And the other part in bitcoin would be like a DCA that I can do without even thinking about, and since they would go in a BTC wallet I like the idea that I wouldn't even see that money, so no temptation to buy useless stuff just because I have some extra money.
Actually receiving in bitcoin for payment salary more interested than fiat but depend with bitcoin price, when bitcoin on higher price seems more profitable receiving with fiat because potential of bitcoin get correction after salary receiving. But get more increasing the values of salary when bitcoin get correction but I doubt any company want to change of payment salary every time.
There are two scenarios here.
Scenario 1: If BTC would be globally accepted, which means even the small stores nearby your house would start accepting BTC payments then I would opt to receive my 100% salary in BTC.
Scenario 2: If BTC is not yet globally accepted, that is the current scenario, in that case I would accept 50% of my salary in BTC and the rest 50% in fiat.
I don't think any company want to make this scenario for salary payment, its difficult to pay half in fiat and left half in bitcoin because they want to make all the same payment way for salary as fiat or receiving in bitcoin. However bitcoin still not acceptable as legal payment currently and difficult to receive salary trough bitcoin for offline working.