@Enjou You're going to have to convince me about the Macerator + Burning Log thing. I
don't think the Watchers might take notice but
do think Jiraiya will realize that if we added more logs the corresponding fireball would make the Watchers take notice. Very risk-averse to showing this, since the benefits (cool fireball seal, J-man probably has them) don't outweigh the costs (J-man realizes we didn't really take to heart his Watchers talk) FMPOV.
The risk should be minimal. We already know how to do it and that it works. The Watchers, who are apparently so powerful that they could track Jiraiya on a mission without anyone on either side noticing and then break past all of his defences with apparently little effort, have not seen fit to give us a warning. (There's a non-zero chance these Watchers would have noticed our activities and have been watching us for a while - perhaps they were watching Kagome, for instance, and have been watching us since then. Or they're nigh omniscient when it comes to seals.)
If you have a concern about Jiraiya saying we haven't taken his advice to heart, then the proper response is to show him what we have already developed and ask him for his advice on whether or not it should be used, expressing our concerns in the 'bigger explosion' department. There is not much chance for harm in asking the older, wiser sealmaster his opinion under controlled conditions, and then basing our future actions around his advice. Also, if the Watchers are watching us right now, then them seeing us ask Jiraiya about concerns of "Will this be a problem?", "Should I not use this?", and "Should we avoid taking this concept further?" should make them more inclined to think we take their directives seriously, and thus will be less inclined to take hostile action against us.
The risk of potential harm or death from being too afraid to use a weapon we have that isn't that bad because we couldn't even bring ourselves to ask Jiraiya about it is much greater, IMO.
At worst, I would suspect that Jiraiya would state that we should keep it as a trump card for emergencies and keep this Macerator variant a clan secret, and not put it into active use by Leaf or for ourselves in general. But at the very least we won't be wallowing in ignorance of the matter.
For the benefit it's possible he may not have a good seal for making a big fireball, or what he has may be something that is harder to infuse (and thus riskier) for the same level of effect. An easier to infuse but still effective fireball seal would be a good benefit, because it would decrease the chances of infusion failures and all that entails.
So, the best option for these concerns is to just add a couple of sub-lines along the lines of "let Jiraiya know you came up with this prior to coming to Leaf" and "ask Jiraiya if he has Watcher related concerns about this" so that Jiraiya won't think we ignored his warning.
