Red hawk is an evolution of Gomu gomu no bullet. Which has no Jet form. At Least to be seen. Nor can it evolve into a gattling which is an evolution of gomu gomu no pistol.
I made a flow chart to understand better.
A basic punch<
As for the strongest its not red hawk, its either storm or Gatling gun
While it is still debatable to say with Haki equipped and second gear whether or not Gomu gomu no storm would be better than elephant gatling because before gears Storm was always superior to gattling so after the supplemental technique would be applied Would a
Giant Jet Gomu Gomu no storm With haki out Match a Giant Jet Gomu gomu No Gatling gun with haki equipped for maximum destruction..
And lets not even get into Thor Or Tag team combos. Plus we have gear based supplements. And Haki now to add into the mix. But by pure destruction its definitely a debate between storm and gattling with maxed out gears and haki.
In short there cannot be a Gattling red hawk. And Red hawk is not his strongest technique due to the fact that its a precision killer and wouldn't in a head on collision stand a chance against a giant jet armament storm or gatling.