With these short telescoping masts, you’re limited in antenna experiments, of course.
I have now read again in the old Rothammel… and : There is a recommendation for an EFHW with 2nd element.
In his version he takes a gamma match… but in principle it is probably feasible. In the chapter later he even explains that center-fed radiators in vertical beams have disadvantages, because the feed cable is in the way and thus adversely affects the antenna… and reduces the gain… to 3,5 dBD
I think I’ll be back at antennas soon… and Ignacio is to blame 
73 Armin