even if i had money to burn like you apparently do, i would not do it, career or not. you can do much more multi or general fun hours for same cost.
for the same cost you can buy a pack of multi hours. single-pilot Multi ifr in serious ifr conditions is a challenge.
a 737 is just heavier and faster than your average multi. I think that sim checks in companies are a bit contrversial, i have seen instructors with 1000s of hours fail them just because they did not master some of the SYSTEMS on anew type, but they damn know how to fly (ex-military jet).
In fact, commuters in US put you in a general ifr sim, and not full motion type-specific, which makes more sense.
General experience is very more important also (weather, atc, ..)
All airplanes fly tne same, only speeds and weigth change (just read the poh.).
Almost anyone can read a POH and master the systems (airplanes aren't that complex), especially after the JAA courses which are a bit of an overkill.