I've tried heal/toe shifting, and have just never understood the point for modern vehicles. From what I understand, manuals didn't have syncros back in the day, so you needed to match revs when downshifting. When you needed to downshift while braking (for a corner, etc), this means heal/toe technique was required.
Today, why bother? Not necessary for downshifting for my '88, '89, nor '04 daily drivers. Downshifts just fine. If you aren't yet used to the clutch in a recent purchase, OK. Hold the brake and apply some gas to get you going on a hill. Then again, if you have a hand-brake, not necessary. For a vehicle that you are used to, I prefer to simply apply the gas and let the clutch out, however is necessary to do the job. No major slipping. Just do it quick enough so it doesn't stall.
thebrakeman ('70), DW ('71), DD ('99), DD ('01), DD ('05)
2004 Surveyor SV261T (UltraLite Bunkhouse Hybrid)
2006 Mercury Mountaineer V8 AWD Premier
Equal-i-zer WDH (10k), Prodigy Brake Controller