You're not alone, I have the taller Harris and it's awkward at best. 6-9 is better. I'll add a second vote for ponying up the extra funds and investing in an Atlas if it's possible. It can be shuffled around to different rifles in a matter of seconds. And I've found that is it a much more versatile solution for a wider variety of shooting situations. And adding a short rail section to a fiberglass stock isn't hard. It's worth the initial efforts.
The Atlas is more versatile, no doubt. I use it on my competition 6.5 Creedmoor, and my LR308. But during load development, zeroing, and getting DOPE on a rilfe, I feel more stable on a Harris. The Atlas, at its shortest length is a little taller than I'd like, and there is a little bit of play in the notches on the hinge.