  Measurements on mass , angular distributions, fusion-fission cross-sections
of fission fragments from actinide nuclei $^{249}$Bk and $^{257}$Md, produced
in fusion reactions $^{11}$B, $^{19}$F + $^{238}$U, and comparative studies
with projectiles $^{12}$C, $^{16}$O,$^{30}$Si on same target with help of
existing works are presented. The measured mass distribution data agree well
with statistical model GEMINI++ predictions, the measured angular anisotropy
data for $^{19}$F + $^{238}$U reaction exhibit deviation from the Transition
State Model (TSM) results at energies below the fusion barrier. The fission
cross-section data are reproduced fairly well using the coupled-channel CCFULL
calculations. The microscopic TDHF quantum calculations also show no
significant interplay between the orientation of the prolate deformed $^{238}$U
whether tip to tip or side by side collision. Fusion-fission mechanism
involving projectiles with atomic mass (A) 22 and charge 9 on actinide targets
in the actinide chart are dominated by shell manifestation comparatively
colliding partner's variables in reactions.
