If I am right H1299 are non-small-cell-lung cancer cells (NSCLC).
The "dimensions" or these cells will markedly vary according to whether they are cultured in "2D" or "3D" environment, and if in 2D, on which type of extracellular matrix component(s), i.e. from single ECM to complex ECMs such as Matrigel, etc...
If you provide us with some indications on the experiment(s) you have in mind, I can may be help you, and if not me, by definition RG members.