#1
Hi.
I'll play in death metal band soon and I need to change strings. We will be playing in C# tuning.
I want to put Ernie Ball to my RR3, but I'm not sure what gauge will be good enought.
As I play in E, I love using 10-13-17-28-38-48 (mixed 10 and 11 gauges). I loved it because of the thicker feel of a wounded strings than a regular one.
And I thought that mix of Beefy Slinky and Not Even Slinky (11-15-22p-32-44-56) will be a good way to go, but I am not sure about this. I am afraid that plank stings will be too loose and wounded strings will be too thick.
#3
I do a lot in C# Standard and with a 25.5" scale guitar I tend to use Ernie Ball "Not Even Slinkys" (.12-.56).  But even then sometimes I substitute the lowest string for a .59, depending on the technicality of the riffs I'm doing.  I just did that yesterday, in fact, because I'm in the process of recording a pretty technical, high-BPM blackened death metal song and the looser .56 was just not responding fast enough.  I like quite a bit of tension though -- considerably more than what most people like, I think.

There's nothing I hate worse than picking up a guitar, trying to play some fast, techy riffs, and my pick just wallows in yesterday's soggy spaghetti noodles.  I generally can't walk into a music store and actually play any of the guitars off the wall -- they're strung far too lightly.
#4
I have a guitar tuned to C, I got a set of GHS 11-70 on it with a plain 3rd (either a 19 or20, can't remember which) Might be a bit heavy for C#, but you never know 
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