There are so many RG cables that acctually RG-6 is not really the one with less losses, RG-11 for sure is better and more expensive and running from memory now, RG-8 is even thicker therefore less losses and even more expensive. In any case like NFastro says , use RG-6, is better than RG-59.
Once again I would mention this, The 8 bay antenna is not designed to be hinged or aimed half of it one direction the other half another one. This is just a lie (non cubans I think call it eufemistically a marketing gimmick) , subjectively users might think it works better but theoretically and prosfessionally that is not the case.
You should choose your antenna system accordingly by using rotors or other type of antenna (wider beamwidth) rather than simply putting 2 of them and aiming them in different directions.
Only consider an amp (pre or not) when long cable runs or multiple TV's scenarios , in most cases , selecting the proper antenna (gain, beamwidth) is the way to go and solves the problem. Is like with FTA satellite signals , you see people putting 20 cad inline amps when they shopuld have bought a bigger dish with those 20 dollars in the first place.
I suggested that antenna not because it was cheapie but because it has VHF capability (long center dipole) and in 2 cases I tried in center Mississauga it pulled everything the CM4221 was pulling. Besides for an attic install weather is not an issue, this antenna is not as mechanically robust as the CM 4 bay BTW. Even more important other than CW, PBS , ION and the US Ads the rest of the networks from buffalo basically have the same programming our Canadian stations have , even at the same time!. Not to mention who watches the subchannels anyways! or who has the time to watch that much TV anyways!, lol.
In regrads of Roof installs (although it may not sound good advice) you should avoid them if possible , always consider chimney, brick walls or even a tower first. I am not a roofer and maybe too paranoic but the less you "damage" your roof by attaching to it the less likely you might have problems in the long to very long run with roof issues. Pretty much like with security the best kept secret in the world is the one that you took to your grave not the one you "protected" by hidding it in the safest possible safe at the highest secured bank.