I also use a battery powered frother (for milk, including powdered when necessary) – it works great. It is mostly for car camping, and is in my coffee "backpack", which also include an Aeropress, a tiny Japanese ceramic burr grinder, and beans roasted the day before. People car camping with me scoff – until they see the results. :-P
I like matcha too, but think the idea of tea bag matcha is abhorrent. It reminds me of the joke about white chocolate being for people who don't want the taste of chocolate to interfere with the experience of its texture. On the other hand I don't have any purist cred since I also like matcha lattes with honey drizzled on top sometimes.
A regular bamboo chasen, including the plastic case, may be the ultralight option for this anyway. Admittedly the form factor and fragility leave a lot to be desired. Mine are about 0.35 oz – but if I drill holes in the handle I'm sure I could get it down to < 0.2. With the plastic case it does comes to a whopping 2.0 oz in total, but we can start a thread (so like this site) about the lightest protective case for a chasen. Store it inside your DIY beer can pot maybe, or wear it around you neck on a lanyard.
Rick, while taste is something that varies genetically a great deal, if you use FRESH matcha bitterness is not the predominate flavor at all – at least that is my experience. But the good stuff is expensive and you can't just use it now and then – it will be crap after a few months, even vacuum sealed – and then it WILL be bitter.