I hope I'm not stating the obvious here but the 152mm Ektar is a great lens but it won't cover 8x10... maybe not quite 5x7. Are you using a reduction back? If so then this is perfectly practical.
You can make a recessed lens board by adding a metal cone (perhaps from an old enlarger) to a flat board... assuming your boards are large enough to allow this. Just make sure it's large enough to get your fingers into so you can adjust the lens and small enough to clear the front standard's opening and allow for movements.