We ran total loss on all our road race Hondas and I have done a few races at PI with a simple lead acid battery back before anyone had invented LiPo batteries. Road America tended to suck all the available electrons out of a bike using Dyna ignitions. I have little experience with British ignitions, but I am not a fan of that seventies technology in Boyer and Pirhana/Newtronic systems but I know people that use them and like them..
That said, I just sent a TZ self energizing ignition to Rex's Speed Shop in the UK for new internals.
If it were my bike, I'd pay for an HPI or Electrexworld self energizing system or get a Motoplat or PVL system. Oddly enough I still have a NOS Motoplat that Todd Henning supplied decades ago for a CB77 that I never built after I dragged all my spare parts over here from VIC.
As a second option - Plan B - I would try an RC car/plane Lithium battery at a local track and see how many laps it lasted. They are not expensive as long as the ignition is OK with 14.8 volt supply.
Ignitech is good up to 16volts I believe, but I have no idea what a Boyer will stand. Try it and see. If it dies, get a fully programmable Ignitech and use some of the fancy features such as speed shifting and 2 stage retard for full power launches off the grid.
So many options, so little time to try them all. What a time to be alive and racing motorcycles.