Coleman: I'm a relative newbie, but have spent quite a bit of my time practicing toeside, as my goal is kiting in waves. I know exactly what you mean. When first trying toeside riding, I could only do it nearly straight downwind, doing figure 8s with the kite. Gradually, with practice, I've been able to dig my edge in more and and I can now hold my line or go a little upwind while riding toeside. So, riding a surfboard, with straps, I can usually ride "regular foot" the whole time, without needing to switch stance.
But, toeside riding for me still has probably 10-20% less power than regular heelside riding. Meaning if I'm in low winds, I may have to switch feet position every few tacks to make some better upwind progress when I'm right hand forward. Though one helpful thing from this ... if slightly overpowered, rather than trimming the kite, I can take off a little power by riding toeside and be perfectly powered for doing toe to heelside carves along the waves ... woo hoo!
Anyways, back to your question ... for me, I find I have to work the kite much more aggressively while riding toeside, often sining the kite, and sometimes having to do little downwind turns to regain some power. Less so than when I first tried, as I am learning to use the kite power more economically. So there's my answer to you ... practice digging in that edge and working upwind as best you can, sine the kite when you need to.