Well, I was going to vote for "no, never use them... ship them up to us and let us play with them", but didn't see that option.
What I would suggest is that you use them for everything you possibly can in the off-season to learn their strengths and weaknesses and to get good with them so that you can produce parts reliably and quickly.
Then you can make intelligent decisions about how to use them during the build period. It isn't as simple as "small parts" or "large parts"... but rather which parts are most suitable for CNC machining, and what parts can you make with CNC that were not available to you in the past.
Get creative... you have now broken free of 90 degree corners and straight lines!
Jason