I see where you're coming from, but I think that, by sharing all the disadvantages of other clustered designs, this type of engine usage is okay. Certain types of clipping are already used in the Zenith designs -- just take a close look at the Nova's core cluster -- and I don't think that this is much more extravagant. Tight clusters still consume a lot of fuel, are both mass-heavy and part-heavy, and have very high gimballing which can make a rocket unstable. Using Skippers (or worse, mainsails) in a tight cluster will produce an amount of thrust that a lot of rockets can't handle. Clipping engines together mainly helps the rocket look good, as is already shown by a lot of popular designs, and I don't think tight clusters go against that. On another note; Temstar, how exactly do you go about attaching those tail-point engines on the core of your rockets? I can never seem to get them to attach the same way you do. Also, why have you attached fuel lines to and strutted together those engines? Amyway, great designs, looking forward to using them more often.