Well, going strictly by code, you just have to get a #10 solid copper or a #17 CCS ground wire to the mast, and there isn't a limitation on the mast ground wire length, just the ground on the coax can't exceed 20 feet. So you would have to do it just about any way you can. In an attic, it's a pretty protected environment so lightning streamers, utility lines, etc are less of a danger. I think the mast ground requirement came from back when antennas had a 300 ohm flat antenna lead and you couldn't ground that wire. So the spec was probably written to ground the mast as that was the only part of an antenna system you could really ground on a flat wire install. Then, when CATV came along, they often originated their signals several miles away where an antenna ground would be worthless as a means of protecting the consumer. So, a code requiring coaxial cables be grounded probably originated separately of any antenna grounding codes. This would explain the redundancy of grounding that we see from today's OTA systems as well as satellite systems. The code is concerned with protecting life and property and a ground block on a coaxial distribution system should afford that level of protection by keeping stray voltage on a path to ground. However, since the code doesn't present an either/or type of option, we have to do both since we have both an antenna system and a coaxial distribution system.
As a customer who did his own system and is the one who endures the long term consequences, I would say that you should make your own decision on what you need to adequately protect yourself and your home. As a professional install, I have to consider the consequences of not covering my butt on several thousand installs so I follow the code as written, not as I see is probably the case with the above described development of the code.