I took the medical deduction one year, knowing I wouldn't be able to use what I wrote off for HSA distributions. I figure eventually in my life I'll still have enough medical expenses to use against my HSA that I won't ever get taxed on distributions. You can even pay medicare premiums with HSA money.
I don't recall what games I played juggling Roth conversions with the schedule A deduction. I know I did a partial distribution that year. I'm not at all convinced I knew how to optimize it all 5 years ago (or even now, if I'm honest), so I don't think I can help there. Sounds like you have a good handle what the trade-offs are, and maybe you just need to fill out some sample tax returns to see what works best for you.