You can do the math several ways:
It depends on how old you are and how recoil-friendly your body is. Once you get over 50, you're not going to be a big fan of beating yourself up with stiff recoil. If you have wrist or other issues, that time will come much sooner. While some recoil is "fun", a whole bunch is just painful and counter-productive. That will decide the "Major" caliber for your 1911 platform. 9mm is soft shooting, .45 is harsher.
Now for the economic justification:
At a minimum of $220 / 1000 rounds (AE or PMC 9mm here) you would only need to shoot 2000 rounds to spend $440. That's roughly the minimum cost of factory .45 here -- for 1000. So that's your figure for ammo cost.
OK: So buy the .22 top end for your .45 for those days that you're "saving money", and really save money. You can tell yourself that for every 1000 rounds of .22 you shoot, you've saved about $400 in .45 auto, or a smaller amount of 9mm. So you could theoretically shoot that much .45 now, since you "saved" it. Shooting 1000 rounds of .45 should take you a while. I put maybe 100 rounds of 9mm and 50 rounds of .38 down range -- along with another 100 rounds of .22 -- and that's a range day for me. I shoot the .22 in the middle of the other "bigger" calibers and I find my accuracy improves. That, after all, is the goal of shooting: the fun of getting better at it.
So buy what it is that you really want, then buy the .22 top end, and know that you will shoot cheaply and improve trigger control, etc. while snapping off the .22, and then work on the recoil management, target acquisition, etc. with the "major" caliber.
And you'll have the economic justification ready should you need to supply it. Fun and fiscally responsible, now how could you not buy that?