In general, joining antennas is best done using a device meant to merge signals; like a Jointenna, UVSJ or HD Homerun. Otherwise you're likely to be introducing multi-path which can confuse many tuners. Not that it hasn't been done. Simplicity is my suggestion - the best configuration w/the least amount of devices/factors/etc. If you can install a large enough all channel antenna in the attic and be pleased with the reception from just the ENE towers, then you're golden.
To answer your antenna question, the bigger the are, the more directional they are and thus can pull in more distant signal as aimed. Stepping up what would normally be fine outside would be good for the attic to offset losses. Consider that wood and especially metal surfaces in the attic will play with your signal and you may have to tweak direction a bit to reject multi-path signals. So test carefully before you mount it for good. In that testing, check signal strengths on your TV for each channel you plan on viewing. It varies from tuner to tuner, but if the meter drops under 60% or so, you'll probably start to see some signal breakup. So obviously, tune for the best average you can get. It's winter so leaves are few, so if there's trees around, assume some loss come summer when the trees are full sail.
And don't let marketing fool you. "Old fashioned" antennas are where it's at!
There's nothing magical about smaller antennas with "NASA inspired" designs. They just have less gain which is less of a factor the closer you are to the towers.
Good luck!