You can use a Locus Gear DPTE (Dual Pole Tip Extender), which is essentially two tubes with a hinge joint and a loop. The pole tips go inside the two tubes at the apex, inside the mid, poles set at maybe 125 cm; there are cups that Velcro on the pole handles and a cord to stop the pole handles, which are on the ground, extending too far from one another. Maybe each foot (handle end) 6″ inside the tarp, though the tarp does have ties to go around the pole, but I never bother with them. The DPTE and two poles form an A-frame, and really free up the inside of the mid. A little more fiddley to erect than one pole, but well worth it, but don’t puncture the mid setting it up or taking down (often I almost have…)
you want a loop inside the apex to hang a mesh inner. Some attach a loop outside as well to hang the mid from a sky hook, but that risks compromising the waterproofness.
You could instead try sewing two very light tubes (carbon fiber or maybe alu, possibly even polythene of plastic) into the mid, but would need to ensure that the two tops form a hinge, and cannot push past each other, and this time around I suggest you don’t. Better to get a feel for the structural behavior first.
Of course the mid cap goes (is sewn) on the outside of the mid; but apart from the problem of having to have a funnel shape for the pole or two poles or DPTE to push against, you might consider an open apex, which would vent well, then stuff fabric in the hole when it rains. Or have a hood that pulled over it. I suppose some webbing to catch the pole ends, make sure the panels hang properly and can take the strain.
if pole length isn’t/wasn’t such a limitation, I would definitely have the two poles outside the mid, not inside; but the limit is hiking pole length max 135cm plus pole jack of 8 or 10″ or 12″ at most. My old Lekis are 150cm, but even that is too short without extenders. If you are cutting saplings at the campsite, then not such a problem.
you don’t absolutely need a vent at the top, but hot air builds up there; you might consider a tunnel vent set into one panel, which I made for my experimental mid; many older dome tents used that kind of vent, and I rather like them, but I haven’t seen others use them on mids. There’s a photo of mine in a fairly recent thread, but I can’t remember the subject of the thread, sorry. If I get inspired tomorrow I’ll post a photo.
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