The big question here is:is it even worth it for me to keep experimenting with actions when I've already gotten so quick resizing them myself? Is there anything automation can speed up in this case?
I think there are two questions here:
1) Would script/action automation be a good business investment for the job you mentioned
2) Should you be the one that creates that automation
For #1, you did not provide enough information to answer the question. Here is one approach. Take the number of hours in a year that you spend doing this work for your company. Multiply that by your equivablent hourly rate. That is how much the company is spending now to get the job done per year. If the cost of putting a piece of automation in place is substantially smaller than that then it is a good business decision assuming that either a) your time can be spent creating other valuable work for the company or b) the company can reduce your hours and spend less money ( I bet your not liking option b ).
For #2 (which actually feeds into #1), is what would be the least expensive way to implement a script/action to do this automation. You have only considered doing it yourself. The work could be contracted out as well. Sounds like the amount of time for you to come up with a solution is pretty unpredictable which means having someone with more experience in this area may be able to do the job with higher predictability. I am sure the job could be hired out and they could probably give you an estimate on how much it would cost once they understood the the customer requirements. One thing to keep in mind is support for whatever automation work is done. If you do not know how to maintain a script, then over time when no doubt enhancements are needed or you evolve to PS CS6 more work may be needed. So you would want someone that is realiable and would be around in the future ideally.