I would probably go with 4 10000k PC, 2 actinic T-5s, & 2 20000k T-5s if you're planning on going with 4 smaller T-5s. Do you have a good source for T-5s though. Especially replacement bulbs. I can only buy (inexpensively & easily) the 20000k & 6500k replacement bulbs. The 10000k & true actinics are much more expensive to replace. It doesn't matter whether the manufacturer calls them throw aways, I always replace my T-5 bulbs. Most are on their 2nd set of bulbs & the ballasts are still going strong.
However, if you want to save having to buy so many new bulbs, then the set up you suggested would be the easiest & cheapest. You could even get the 6400k HO units now.
So you could have: 2 10000k PC, 2 Actinic PC, 2 6400k HO T-5s & 2 20000k NO T-5s. Cover almost the full spectrum of available k lights
Good luck & continue researching the T-5s before deciding.
Anthony