Without any information or specifications, I'd probably make the tweeter circuit something like the second or third order networks shown on my crossover document. Page 53 shows a good second order with compensation and pages 61 and 64 show good third order networks with compensation.

Since the tweeter and woofer are physically close, you'll probably want a symmetrical crossover but again, it's hard to say without measurements. Woofer specs are important for knowing which of these networks is optimal, and tweeter/horn specs are important for knowing what values should be chosen for R1, R2 and C3. Judging from what you've said, I'd probably start with 8-12 ohms R1, 30 ohm R2, and 0.47 to 1.0uF C1.