Mind, wheat DME is typically 50-65% wheat, the balance (35-50%) made up of 2-row or pale.Will probably use wheat DME and see where that gets me.
Let me add, the mash temp used influences fermentability of the wort. The higher the mash temp (within the range, above), the less fermentable, but it can be quite subtle, and depends on the method(s) used.You'll need to hold the temps between 146F and 160F when mashing
And yes, a prewarmed but turned off oven will help keep your mash pot at the correct temps. A little extra warming halfway through the hour may be necessary, but 2 degrees lower or higher doesn't have all that much impact on the wort fermentability.
I did mini/partial mashes for a long time, using a 2 gallon pot in the warm oven, until I wanted to brew a Witbier, requiring at least 50% raw (flaked) wheat.
That's when I built the 54 qt cooler mash tun and went all-grain.
You could mash a larger amount, say enough for 3-5 gallons of wort, using just Pale or 2-row malt (or wheat or so). Then split the wort into 1-gallon batches, where you differentiate. Such as using different hops for each sub-batch. Or add a potion of different steeped malts to them, such as C10, C20, C40, C60, C80, C120, etc.