DNA concentrations for megaprimer annealing and extension

[WS]

Dear experts,

I would like to anneal two partially complementary pieces of DNA
obtained by pcr  (about 500 bp each with a 50bp overlap) and extend
them (adding dNTP and Pol). So each strand will compete for the
complementary strand an the other strand with the overlapping region.
Is there a concentration range where this might work best?

Next step would be a PCR amplification with end-to-end primers.

Your input is welcome!

Best regards,

WS