When I calibrated my delay in HG/SS, my delay range was 479-489 (yes, it's a lot smaller than in D/P/Pt since the opening sequence is shorter). Emloop or PikaTimer is absolutely 100% useful for trying to hit high delays; it's almost impossible without using one of those programs. As for your last question, yes, if you find a spread you like that's on frame 1, and the Pokémon is also on frame 1, you won't have to worry about advancing the frame at all.
BTW I'm still in the early stages of the game (only have Falkner's Badge), so what's the best way to calibrate? All I could think of is the Sudowuddo, but it might not be enough to give accurate results IMO. I may have to calibrate because we are unfortunately required to go to the burned tower to progress the game (and to create seeds for Raikou/Entei).
Although I have another questions...
If I beat Raikou & Entei, will they be regenerated after beating E4?
If I capture one but KO the other, will the KO'd one be regenerated too?
How about Ho-Oh? He'll be regenerated too if I KO him and beat the E4?