@evosolution: I think you're at a stage where you've read enough and searched the various opinions that it's time you just dive in and start seeing how it goes. If you choose the Conti Carbon glue I would follow their instructions. I've never used it but had the same questions you are asking right now at first. If you choose Vitorria Mastik or the regular Conti glue then you have a whole bunch of different opinions floating around and now you just have to pick and choose and ultimately form your own opinion. That's what I did. Only then will you learn how the glue works while spreading and you'll get used to it and wonder what all the fuss was about. You'll learn just how big, or small, a section of rim you can quickly work with at time before moving to the next small section. Youl'll learn how to work smoothly and quickly to the point of rarely getting glue on the brake tracks yet getting a completelly uniform and smooth application all the way up the edges, and the edges of the rim bed are where you really want the best bond because as has been mentioned, that's where the most forces are acting on it. I use acid brushes to apply the glue, one brush for once around the rim, then start with a new brush. They're cheap and disposable, throw them away as soon as they're getting gunked up and making life more difficult than it needs to be. Also, I find using the small tubes much much easier than from the larger can. You'll learn just how much to squeeze out per section so that it's spread nice and evenly and perfectly timed for the next section. It's all about doing it a few times. You'll understand much more about the process once you do.
I have come to the conclusion that following Vittorias instructions works best for me, and even though I've experimented with more layers, or thicker layers, I find that the bond was just as strong or stronger with two layers on the rim and one layer on the base tape. In fact, I would argue that adding layer upon layer just means you're building up a bed of glue which is really just waiting to melt underneath and possibly making it even easier for a tire to roll off if conditions permit. This is just my own thought however, as I have never rolled a tire or had one otherwise separate from the rim.
Then comes removal. That's really where the "fun" of tubular tires comes in. It took me 15 minutes just to pry the last tire off glued according to Vittorias instructions. And I like to completely strip old glue from the rim before I put a new tire on, unless it's a really new tire and stuff is really fresh. But if a tire has run it's natural course of wear, I like to start fresh. In the old days, all kinds of scraping noises and swearing and drunken battering could be heard from cellars as this process took place, but now with chemical strippers etc, it's still time consuming but relatively painless. In Europe there is Schwalbe's Tubular Glue remover available. Here in North America is it unavailable, but I've come across a product which I suspect is very similar. It is called Klean-Strip Adhesive Remover. I find that working in small sections with this stuff (and a whole bunch of acid brushes) will get me to rim bed that is indistinguishable from a brand new wheel. This works much better than Goof-Off for getting the majority of the stuff off then I'll use Goof-Off for a few remaining bits, but probably not necessary. I only use Acetone for a wipe down of new rims and a quick wipe down of the rim upon glue removal.
For what it's worth, here are the maufacturers instructions for the use of Vittoria Mastik One:
And here's the mess after removing a tire and all related glue, leaving a perfectly clean rim ready for a new tire...
Oh, and one last thing I'll add regarding tubulars is that I am in the camp that believes aging tubulars is a complete myth, and that even if it were true years ago (and I'm not saying it was even then), I have found nothing to make me believe it is true today. In fact, the only tire that I've flatted in a normal way (small puncture that was easily fixed with sealant) was on a tire that had been aged the longest before mounting of any tire I've used. And I'm not implying anything there because because I don't believe aging does anything except allow a perfectly good new tire to become old; the flat was caused by running over something, plain and simple, and it was small at that. Rubber ages, becomes brittle, and ultimately unusable. I have an unridden mounted Vredestein tire that has been in my nice cool dark garage for years, and it is cracked beyond hope. Unusable. And I once went touring in New Zealand with my touring bike that hadn't been used for about 3 years with nice Continental Top Touring tires on it. Lots of tread but I had to replace them after the trip started due to them crumbling and cracking. So, if you want to keep a bunch of tires sitting around somehow believing they will be much better when you finally mount them, go ahead if it makes you feel better. But I'd rather just get the latest and greatest tire when I need them. Sure glad I don't have a bunch of Veloflex 22mm tires lying around, they're great tires but I prefer the 23's and am now experimenting with the 25's, and am liking them so far as well, and may become my size of choice in the future.