One hell of a lot of older Colt Single Action Army revolvers started life as .32-20s, .38-40s and .357 Magnums and were later redone to .45 Colt - thanks in large part to the popularity of small-screen Westerns.
I'll say this - having owned a 5 1/2" .357 - the .44 and .45 versions are much lighter feeling when handling the weapon, than are the smaller calibers - they feel more 'alive', and for me, they instinctively point better.
Keep an eye out for a .357 cylinder - it'll allow you a much wider choice of bullets and performance.
And - keep saving your money.
Good Luck!
Vaya,
Scouts Out!