Mmm. Dennis Had FireBottle. I enjoyed my time with one for over 6 years. I also had an LP-27 preamp and still enjoy his CJ5 pre, even though it's now out of fashion. There's newer from Dennis in the mix.
If your speakers are efficient enough, it's definitely fun to try different tubes in the low power SEP amp. But there's also something to be said for generous headroom for any speaker, let alone the most efficient. Having more than one flavor of amp handy can be very enjoyable.
soix, they might buy your 0.5 at the SMC shop. No promises, but it might be worth a conversation.