Let me ask a question regarding organization.
Which would be better?
Total Warfare, 2 Tactical Operations, 1 Tech Manual, 1 Interstellar Operations, and 1 Strategic Operations (6 books)
OR
1 Battlemech Manual, 1 Combined Arms Manual, 1 Aerospace Manual, 1 Fleet Manual (4 books).
Because for standard Tabletop Battletech play (i.e. not Alpha Strike, BattleForce, Campaign, or RPG), that's what we're looking at.
Techmanual should be compiled with your tournament rules, and just don't include the advanced options you can't use in a Tournament. Those can go in the next book up.
Basically, the BMR(r) should be the model for your central core book, because it lets players play with all the of the SYSTEMS in the game without being burdened by exceptions like quirks, or weird shit players won't use like Airships.
SINGLE rulesets. Only one scatter method or diagram for indirect fire, for example-anyone who wants a simulationist version can buy the optional book and find players who'll accept doing that much extra math. One tweak I'd recommend for TOURNAMENT rules, is that air-dropped ordnance be balanced against ARTILLERY IN THE SAME RULESET, as in cutting out the weird ass situation where one ton of air drop munitions does less blast damage than a fraction of 200 kilos of artillery shell.
(if you can streamline a long tom round that much, you can do even better with a dropped bomb that has five times the mass fraction and occupies a lot more space.)
You don't put things players aren't likely to see a whole lot in the Tournament book. So LAMs go in the next book, (or a later book) same with Warships, mobile structures, Blimps (what are we, Steampunk? come on...) and so on. Your tournament book should be basic enough you can hand it to a newbie and they can use and comprehend it. Suggested: Sixth Grade Reading Level, because that makes it easy to teach.
Second book should include the harder to calculate stuff, like Infantry construction, some of the variations on scatter, mobile structures and support vees.
Book 3 is your strategic warfare book and focuses on Warships and strategic scale assets. This is a redress of Battlespace. Include weirder stuff like large wet-naval and Alpha Strike rules here. Book 3 should let players plan out and carry out
Planetary Assaults. and invasions.
You know the kind of battles that can't be won by a single lone heavy equipment operator in a man-shaped giant exoskeleton, but actually hinge on logistics, strategy, and all that stuff that can't be solved in a skirmish.
Three books, not four. Going from Skirmish to small battle to Large battle.
A hypothetical 'Book four' would be a campaign builder for outright WARS. Think "Risk, but with Battlemechs" or similar vein, Starcraft on the table top, maybe, but influenced by, and influencing, the use of the prior three volumes. (aka the rules logically and consistently progress from the tournament level to the battlefield, from the Battlefield to the War Zone.)
Basically Book One should have enough about your BV system to let players build up a Battalion. Book Two should include enough campaign rules to build a regiment or Regimental Combat Team, book Three should be a guide to arming a periphery state or province, and hypothetical book 4 should be sufficient to play out the clash of nations across a few years.
Then for your Traveller/completionists out there, a "Fire Fusion and steel" equivalent that goes in-depth on other eras, *Primitive tech, how to advance tech, how to change the price of it based on volume and resources.
Yes, that's five books but they're five books where if you only wanna play at Battalion or lower? you only need ONE book the others progress it in terms of SCALE and Campaign DETAIL.
but you can hand out the first book at ye olde gaming store, and with a pad of paper and some pencils, you can have a game going even if nobody has a tech readout, or nobody has the right one.