Stacked yagis, will this work?

TL:dr would stacking 4x 5 ele yagis on 70cms, vertically, and pointing roughly 40 degrees apart from each other produce better gain than a traditional 4 stack dipole in the same config?

I made a test antenna stacking 4x 50 ohm dipoles vertically, fed with a matching coax line to phase them. This works ok.

I'm trying to achieve very high gain in a 4 mile radius extending 180 degrees from the antenna (70cms repeater) to a HT. With the current setup, a few miles away in (brick) buildings the signal is quite low.

Beyond 5 miles there is a hill so a very narrow vertical beamwidth is fine.

I'm wondering if instead stacking 4 x 5 ele yagis (60deg H beamwdith) would improve the near coverage?

I'm only covering 180 deg so there would be some overlap in H beamwidth and E should be pretty flat.

Base antenna is at 21', this cannot be improved.

The coverage area is on slightly lower ground (50' or so lower).

Any thoughts?

Edit: I can't have an x510 or x700 as the visual footprint is too big. 4 stack is only circa 8'