I have 6.3:1 and i feel like its good enough. I was looking into buying another rod for spinnerbaits/lipless cranks, and possibly doing some jigging. Is i high speed reel needed for this application? What are pros and cons?

I use a high speed for my worm and jig rod, so that I can get slack in very quickly to get good solid hooksets

You don't, its a convenience. Nice for jig/worm rods, and really nice for burning traps.  I remember when 5:1 (24 IPT) was called "high speed."

How light of a lure can i cast with a casting reel. like 1/16oz?

How light of a lure can i cast with a casting reel. like 1/16oz?

Casting light baits is not all about the reel, a reel with a shallowlightweight free floating spool with good spool supporting bearings can cast very light lures, IF paired to the right rod and the light line.

http://www.***.com/Team_Daiwa_Advantage-A_Casting_Reels/descpage-TDACA.html

So somthing like this? it has a free floating aluminum spool. and for a rod would a 7' M work?

Not really, it will with the right rod, the right line, the correct brake setting, the correct cast control setting and a very educated thumb but not well; the spool is too deep ( see the line capacity ), deeper spool ---> more line capacity ---> more line ---> more overall spool weight ---> more resistance to start up the rotation of the spool.

This one will without much effort:

Apparently there 's been a severe cut in baitcasters capable of handling light baits with ease, we had a lot of them on the past years:

Curado 100/101D

Chronarch 50/51 Mg

Sol

Man, those were great reels for fishing light baits with light line.

Buzzbaits. I usually buy a 5.1:1 because i can vary the speed. You can make a fast reel slower, but you can only max out a slower reel.

For throwing 1/16th oz you would be better served to use a spinning outfit. I've got two of the HSTA 153 reels, and I like them alot. I think they are under - appreciated.  There are better baitcasters for throwing ultra-light weights though.  But regardless of which baitcaster, at 1/16th oz you are still going to be better off using a spinning outfit. and you don't have to have a 7 to 1 reel to fish.  The 6.3 works good for everything. in fact I wish they would make the Curado with that speed.

Thanks for the feedback fellas. Ive been lookin at the curado for a while and i was deciding to get a if i should a high speed reel.

Curently my Daiwa procaster(BC) is 6.3:1 and my Daiwa regal(spinning) is 5.1:1. Now that i think about i think my spinning skills are pretty good now to where i can control the distance pretty well. I really want a curado and i felt like i needed a high speed reel, but money aint on my side atm. Haha, gotta get a job...