BOOMAS?! I hate those things. . . they have weird faces.
RED RING RICO and I share a common belief. . .

Booma's aren't neccesarly a problem...unless there in a large group that's when you hope you have some hp left after this. But out of all of the materials I found hp materials to be the hardest to find.
Thay are really easy to find with a Redria character. I just gave all the materials to my android. I kind of regret doing that. . .
. . . I have no idea. I thought a while ago that they affected your total amount of materials you can use. But later I found out they didn't affect it and now I'm OK.

Yea. Stuff.
I like HP materials now. I find them occasionally, and they help out a bunch.
I hardly ever find HP mats, although for me the TP mats are the hardest to find. In my entire PSO life I've found maybe five. Although the whole limiting thing, I never actually knew about it. I heard about guides on how to maximise your character's stats, but didn't take any notice of it.
I've only ever so far ound one TP material.
TP Materials are only available online unless you are playing offline Challenge Mode... in which case you cannot use those on your regular characters anyways. I'm not sure how it worked for PSO DC, but on PSO GC there are simply no TP Materials offline.
The only three places that come to mind online where you can find them are the quests:
Rappy's Holiday (From the 3-button lottery game)
Gallon's Shop (Using Lucky Coins to play Lucky Roulette)
Today's Rate (From spending a large quantity of time fully completing the quest.)
That's all though. Which is why my character's not maxed on them... too much work. XD