I would say that the answers to your questions depend on your own preferences and also on the amounts you plan to invest. When it comes to self custody and security, my thinking is that there is always something to improve (I’m also still learning). But for example, you could also split your coins on several HW wallets and store them in different places.
Shielded transaction support for HW wallets is also in the works, for details you can check out the work done by hanh/Zondax: Shielded Support for Ledger Hardware Wallets (NanoS+, NanoX)
And Trezor (seems on hold for now): Trezor support for Zcash shielded transactions - #63 by Kat.Trezor