Hi and welcome Armydad!!!!!!
It's nice to have a few more guys here; gives us chicas a different perspective!
I also have a DH whose work sometimes runs so early and so late that he doesn't get to see one of the girls at all once in a while, and very limited time with the older one when that happens (he works for the DoD), so I can kind of relate from the wife perspective. Fortunately, his current boss is understanding about family time, and his current situation USUALLY supports his getting home at a decent hour; if only Washington DC traffic would consistently cooperate!
Anyway, I'd say that the best thing you can probably do is spend as much time with your DS (that's Dear - or Darn, depending on how you feel at any given moment!
- Son) as you can so he's comfortable being around you. I wouldn't worry too much about a good sweat making him nervous, but if you think it might be an issue maybe your DW can hold him while you and she catch up while you shower and DS can at least hear your voice and you can play with hm directly afterward? (gently, of course, so as not to wind him up before bed
Just your presence as often as you can spare it will help amiliarize him with you.
As for night wakings, I discovered that with our firstborn (now 4), if I sent DH in to do night wakings, he didn't smell like milk so she'd settle more easily for him not expecting a feeding, That doesn't work with DD#2, who thinks that Daddy is her personal plaything, and if he's there he's there to play, and if she wants a feed she'll yell the house down and otherwise she'll wake up happy to see him and wanting to play. This isn't too restful for me, but she's a stubborn little thing and that's the way it is, at least for now. I do manage to stuff her as full of calories as I can in the afternoons and evenings and we hope for the best from there.
The high-pitched voice? Even basses have falsettos for a reason!
Seriously, though, both my DD's seemed to get a kick out of the differences in DH's and my voices. When my DH uses a falsetto, though, it tends to make the DD's giggle, so use sparingly!
If you're going for pu/pd, you have my admiration. I never managed to do it with either of mine, as I'm more of an instant-gratification person AND I literally can't stand the crying; it sends me around the bend in a hurry. May want to check out the appropriate forums, read/download Tracy's Sleep Interview (try General Sleep forum?), and make sure you and the wife know what you're in for before you get started so you're on the same page. Otherwise, all I can say is GO FOR IT!!!!!