I'm not sure in the 1/4 and 5/8 wavelength elements, they should be about 1/2. Bandwidth can not be so wide because coil is resonant structure, about 100MHZ at vswr<2 is expected.
Ground plane can be replaced with a coupler(tube around first element).
Specify your diameter of elements and coil wire(suggested is about 3-4mm because wider bandwith, but question is can you made :shii: a coil from this wire ).
For one element gain is about 5dB, for 10 about 12dB.