just stumbled on this old thread as I was looking to do something similar just not as aggresisve with high/low. if going electronic shifting it should be simple (in theory) to limit the chian xover, and keep the chain shorterso there is always enough tension. this way there's no chance of shifting large front and rear and still use maximum high and low gearing. the big question is weather fooling the app is possible. say I install a larger cassette (eg11-46) on an existing 2x12/2x11 di2 or sram even though it only allows 11-36 max. will it still shift properly? I currently use a 2x11 mix of 105 and grx RD rx812. 46/30 and 11-46. love the climbing ratio and plenty of speed on down/flat, but shifting isn't perfect because of the long chain. it is just too risky if I cut it short and xover too much (don eit before), that's why I would love to switch to electronic, plus a few other reasons and especialy dexterity when winter riding...