It's easy armcharing this
Ok, so here's a couple of "little" suggestions. If you do this right, you can get the digiflite and later fit it in the same opening as the digitrak.... OR.... a maybe better (or different suggestion)... Think of those lower instruments as "backup"... Give yourself the "standard 3", like I did, in an order and fashion similar to where they are in a 6pack and center them in front of the pilot. If the EFIS goes Tango Uniform, you still have basic flight instruments.
Ok, so to do that I would suggest, grouping them around the pictopilot (whatever it's called), as the AI (or does it only function as a TC? Don't they have one that works as and AI as well, with AP? - Might be as much as the digiflight tho...).
At some point, you are not going to know if things will fit until you set down with a cad guy and real measurements and lay this out. That was the only way I could figure mine out as a final.
Lastly, and I don't want to scare you away, but those 2" guages are EXPENSIVE!!! I don't know unless someone has come out with less expensive ones, anyway to say it. The Mid Continent versions are about 2-3K each!!! Maybe there are some that I"m just not aware of.... One last fading comment... Mid Continent came out with a 2" CDI at OSH, it is *very* cool And maybe you could get a backup CDI in that space as well, if you can figure out all the other placement issues.
It's looking really good. BTW... I also developed my panel for future growth... For example, the SL-40 won't be there from the beginning, and I don't say this very loud, but I did my steam gauge spacing such that I could replace the AI with a BMA G4/Lite as an EFIS backup/CDI backup.
BTW, for those reading, the easiest way to get a 3" - Electric" AI, is to buy the Sporty's certified TC replacement unit. It's made by castleberry and it is TSO'd, but *way* cheaper than getting either of the other all electric AI's...
Good luck and keep us posted.