I own a Fender Blacktop Baritone Telecaster that with 12 gauge strings. I like being able to tune low without string flapping, the larger frets (my hands are kind of big), as well as the increased control over what strings get bent/plucked. I also have been practicing with it in standard E tuning because it gives my hands a great workout (if performing I play with 11's, and if it's a guitar with 25" neck the tension is even less which I find an ideal tension for performance).

Reading some posts however I'm worried that standard tuning with 12's on a baritone guitar might be too much tension for the neck. Are there any modifications I can make to ensure the guitar doesn't warp under the tension, or are 12's in standard E tuning completely out of the question for baritone's (and if so, would 11's be ok?). It is currently my only guitar so never tuning to standard E isn't really an option for me (for practicing). If I should never tune it to standard E unless with light strings (<10), I will probably have to trade it in for another guitar, suggestions are welcomed for a good fit for someone that has larger hands and likes strings on the heavier side. Thanks in advance!
Is there any reason you can't tune it down at least a few half steps? D standard, for example. Will play just like E standard.

Having a really strong fretting hand isn't all that important. For some, it might even be a bad thing because they might subconsciously apply too much pressure to strings with less tension, causing the pitch to change.
Ibanez Prestige RG852MPB
Ibanez Prestige RG652KFX
Schecter Loomis NT
EVH 5150 III 50
PRS 212 DB
Line 6 POD HD500X
Deadhorse OD/Boss HM-2
I often play along with 'jam tracks', or practice songs with my son in Rocksmith, which requires original tuning, I guess I could capo but would rather not if possible. I agree that it can be detrimental at times, when I pick up a guitar with 9's I definitely fret too hard causing pitch changing, or overshooting bends. But I feel like I can transition to a lighter touch fairly quickly if needed.

I use the extra tension not so much for fretting but for bends in leads that are often a stumbling block for me (partly because I like heavier strings to begin with, < 11's just feel too flimsy for me and I think gives too thin a tone, and I constantly break higher strings) . My fretting hand gets tired with successive quick bends (i.e. freebird solo), bending + vibrato was always challenging too. If you think I'm going about it wrong I'm all ears, it just seems like an effective way to build strength while practicing.