Sleep deprived nerd

A rambling post discussing a topic that I'm sure has been tread into oblivion. It has been established in a WoB that Aon Dor can, with an appropriate investiture infusion, replicate pretty much any investiture in the cosmere. We have seen a hint of investiture absorption abilities that Sigzil seems to have gained from a very brief time holding the dawnshard. We also know that with appropriate skill, Breath can be used to expand your soul. I wonder if increasing the "size" of ones soul would also increase the strength of one's allomancy. Further, based on all of this, is there anything we have seen or learned that would indicate Hoid is not now able to expand his soul increasing the amount of power he can get directly from the spiritual realm using allomancy, then use the investiture to fuel his Aeon Dor he gained in Tress? And while he is at it, creating a limitless supply of allomantic metals to fuel these powers?