I'm addicted to foam bodied ants & beetles because they are simple to tie and float great without using floatant. Unfortunately, the best foam I ever used was the stuff Bill Skilton used to make but he told me he is done with that part of his business.
I used to tie fur ants, but now I just use a short length of black cylindrical foam lashed to a hook with a few turns of hackle for legs. My beetles are just coarse dubbing put in a dubbing loop for a body & legs and foam pulled over the top.
Because I never experienced pattern selectivity from trout when I plop a beetle or ant over a hungry fish or suspected lie, I don't bother tying ANY of my terrestrials in more than one size. I also never add bright colored posts or other "sighters," or bother with added legs so I can crank out a dozen beetles or ants in a few minutes.
Even though I am in Les' camp when it comes to plopping beetles any time of the year I get the urge, in the summer when I often spend an entire day fishing nothing but, I always fish them on a light tippet. For me that means 7X or 8X.
First off, I always accelerate then check my forward delivery cast to accentuate the "plop." I have found that my beetles "plop" better on 7X than 6X or 5X. In addition, MANY times a fish that wouldn't take my beetle or ant on 7X was fooled when I switched to 8X. I can't tell you how many times this made the difference for me.