My advise also goes to 30m. In addition to all the things already said, I’d say it’s the band with the nicest skip for you to be able to be chased by hams in Germany and also much more distant ones like in UA9, SM, CT, EA, SV…
Regarding DX, you will have better chances on 20m, but I can’t help mentioning the USA activators I’ve chased on 30m and the VK7 who chased me early in the morning on 30m while I was activating in EA1/CR. However, from your initial post, it didn’t seem to me that working DX is a priority for you. You said your main interest is qualifying the activation.
On my own interest, I’d much prefer you to activate on 30m and have my good chances to chase you, rather than 40 or 60m, where I usually have more dificulties to hear activators from Germany.
73,
I could use my 6 m vertical wire on my 7.5 m pole, good on 20 m and 15 m and sufficient on 40 m. On the lower side a 2nd wire goes vertical elevated. The length depends on the band. I could optimise the length for 30 m. I use this antenna with a small tuner with low losses. I will simulate this configuration and check the radiation angle.
But maybe I will use a new to built EFHW using the mentioned pole.
Guru, that’s right. But depending on the situation (chance for DX and not a hike above my limits ) I will bring my current FT-817 to the summit. The single-band CW TRX is only for some purpose. And it’s for fun - activating with a home (made) reassembled TRX.
I was going to make a not too serious suggestion of 15m - as it has been working very well recently. But I tried it this morning and it was dominated by Russian operators transmitting at 30+ wpm. I tried a CQ call anyway at my gentle 14 wpm and got a “?” back so fast it must have been at 35+ wpm. That was the last I heard from them so I switched to 30m and it was much easier. So another vote for 30m.
An EFHW would be fine. With my multi-band HF rig and its built-in ATU [a KX2] I activate occasionally with a 60/40/30/20 linked dipole but more often with either a 40/30/20 EFHW or a 80m-6m vertical.
I’m assuming taking your [30m] QCX 5W monobander instead of your bulky 1.3kg FT817 is cos it’s fun / a nice change / a small lightweight alternative - ideal for quick winter activations.
As it is QRP and has no ATU, I would go for a [30m] inverted V dipole for best efficiency. As 30m is a narrow band you should get a good SWR on any frequency. My UltraLite wire dipoles on a plastic winder with 10m of RG174 (so you can sit out of the wind) weigh about 450g and would fit in a small dry bag along with the QCX and LiPo.
I’ve been leaving my anvil in the shack recently. I had a think about stuff that I take and never use. Strangely enough, I don’t think I’ve ever needed my anvil on a summit.
My vote is also for 30. All the reasons have been stated above. 40m would probably get more conacts, but 30m is always perfectly satisfactory down here in OE.
73 de OE6FEG
Matt
In 2022 until now I brought my 30 m QCX on 6 Summits, with different success, one time only 1 QSO but later more (6, 3, 2, 6). Fortunately I brought the first 5 times also my FT-817, so had more than 4 contacts.
On the last summit I could use only a 2 m Handheld (useless) and only my QCX and my new build EFHW for HF and got 16 contacts. So the QCX is regular in service now.
Thanks for all the suggestions made in this thread.
) I will bring my current FT-817 to the summit. The single-band CW TRX is only for some purpose. And it’s for fun - activating with a home (made) reassembled TRX.
That was the last I heard from them so I switched to 30m and it was much easier. So another vote for 30m. 
What’s the background to this discussion about anvils?