I don't have a 7mm-08, however I do use H414 in a .30-06 Springfield and .243 Winchester and .243 Ackley Improved. It is a very good powder for both families of cartridges.
I hunt in temperatures from 0 degrees up to 90 degrees using h414. My rule of thumb is that the .30-06 family always uses a magnum primer, loads are developed in the summer in the heat to insure no pressure spikes. You will lose some velocity in the extreme cold, but I wouldn't adjust the load at all. The magnum primer helps remedy this problem.
The .243 cartridges I also load with magnum primers. This isn't necessary per-say, because of the shorter powder column, however, I was always told by my handloading mentor that ball powders should always use magnum primers for consistant and through ignition and that loads should always be worked up using the magnum primers (for the ball powders). You don't want suprises when shooting in the summer.
H414 is really close to H4350 (I use this for a .30-06 AI) and is also an excellent choice for the 7mm-08. You'll be happy with either, H414 is also known as W-760 and is 100% compatable with h414 data, It's generally cheaper and h414 is usually $2 cheaper than h4350.
Hope this helps,
Dan