Ok - the short version.

Location !!!!
Food availability.
Lots of studies on this.

There are + and - to each depending on goals.
Genetics (family history not Fla , F-1, Fx or northern) also plays a part .

FYI Fla and to some lesser extent F-1 or x males are small (much smaller than females and northern males) all things being equal (see above factors). So half your Flas and Fxs may be small.

In some studies growth in Northerns in year 1 (really yr 0) was faster but that may be because of location. Contrary to many beliefs initial growth in yr 1 northern climates is faster in many species (shorter growing season) and may show up in initial growth rates. Flas live longer in southern climates but less (maybe only 1 year) in northern climates due to cold intolerance.