Your intended anchor points will likely be fine.. I'd suggest, though, that you run a separate preventer, not use your vang. Using the vang is fine for long offshore legs where gybes are infrequent. Lake sailing won't qualify for that.
The problem is when you DO need to gybe you will be vang-less during the maneuver; you have to disconnect your vang/preventer, gybe, then reconnect basically all under load. If you leave a standard vang in place and simply add a preventer strop or tackle, then you can ease it for transfer without losing the effect of the vang while you do so.
".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)
1984 Fast/Nicholson 345 "FastForward"